Ch.2 - Atoms & ElementsSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Mole Concept

See all sections

Under mass conversions, connections between grams, moles and molecules are established. 

The Mole 

The mole is the chemical unit for the amount of a substance and serves as the bridge that connects grams to molecules, atoms, formula units and ions. 

Mass Conversions

Concept #1: Avogadro’s Number, Moles, Molecules & Atoms 

The words atoms and ions are used when talking about a single element and the words molecules and formula units are used when talking about more than one element together. 

Concept #2: Atoms to Moles to Grams 

Example #1: Determine the mass (in grams) found in 7.28 x 1028 nitrogen atoms.  

Concept #3: Molecules to Moles to Grams

Example #2: Determine the how many molecules of carbon dioxide, CO2, are found in 75.0 g CO2.

Mass Conversion Calculations

Practice: If the density of water is 1.00 g/mL at 25oC. Calculate the number of water molecules found in 1.50 x 103 µL of water.

Practice: Calculate the number of oxygen atoms found in 783.9 g in copper (II) sulfate pentahydrate, CuSO4 x 5 H2O.

Practice: The density of the sun is 1.41 g/cm3 and its volume is 1.41 x 1027 m3. How many hydrogen molecules are in the sun if we assume all the mass is hydrogen gas?

Practice: A cylindrical copper wire is used for the fences around a house. The copper wire has a diameter of 0.0750 in. How many copper atoms are found in 5.160 cm piece? The density of copper is 8.96 g/cm3. ( V = π x r2 x h )

Additional Problems
How many moles of sodium ions (Na +) are in 56.0 g of sodium phosphate (Na 3PO4)? A. 0.342 mol Na+ B. 1.03 mol Na+ C. 0.114 mol Na+ D. 3.06 x 103 mol Na+
What is the mass, in grams, of each elemental sample? b. 0.0355 mol Ba
What is the mass (in kg) of 6.89 × 10 25 molecules of CO2? The molar mass of CO2 is 44.01 g/mol. A) 3.85 kg  B) 5.04 kg C) 2.60 kg D) 3.03 kg E) 6.39 kg
How many moles of PBr3 are contained in 3.68 × 1025 bromine atoms? A) 61.1 moles PBr3 B) 20.4 moles PBr3 C) 16.4 moles PBr3 D) 183 moles PBr3 E) 49.1 moles PBr3
How many iron atoms are contained in 354 g of iron? A) 9.50 × 10 22 Fe atoms B) 3.82 × 10 24 Fe atoms C) 2.13 × 10 26 Fe atoms D) 4.69 × 10 24 Fe atoms E) 2.62 × 1025 Fe atoms
What is the mass, in grams, of each elemental sample? c. 43.9 mol Xe
Stearic acid (C18H36O2) is a fatty acid found in beef and butter.  a) What is the molecular mass of stearic acid? Give your answer in units of g/mol.          b) How many oxygen atoms are present in 1.000 g of stearic acid? 
What is the mass, in grams, of each elemental sample? d. 1.3 mol W
What is the mass of 4.91 x 10 21 platinum atoms?
Calculate the mass (in kg) of 4.87 x 10 25 atoms of Zn. A) 1.09 kg         B) 1.89 kg             C) 5.29 kg           D) 1.24 kg               E) 8.09 kg
How many moles of lithium phosphate are in 85.7 g of this substance? 1. 0.306578 2. 0.341986 3. 0.676199 4. 0.386893 5. 0.265989 6. 0.531978 7. 0.717652 8. 0.60452 9. 0.17272 10. 0.740105
The number of atoms in 9.0 g of aluminum is the same as the number of atoms in _____. A. 8.1 g of magnesium B. 9.0 g of magnesium C. 12.1 g of magnesium D. 18.0 g of magnesium
Calculate the number of carbon atoms in 4.56 grams of ethanol (CH 3CH2OH). 1. 2.53 × 1026 atoms 2. 1.19 × 1023 atoms 3. 1.79 × 1023 atoms 4. 5.49 × 1024 atoms 5. 5.97 × 1022 atoms
What is the weight of O in 742.0 g of citronella oil that has the chemical formula C10H18O? a. 19.31 b. 18.52 c. 77.10 d. 115.5 e. 231.3
What is the mass of 1.3 x 10 13 moles of N2  in pg? a. 3.64 x 1014 b. 1.82 x 1014 c. 1.82 x 1026 d. 3.64 x 1026 e. none of the given answers is even close to being correct
A single atom of a certain element has a mass of 3.352 x 10 -23 g. The element is a. Ne b. Co c. Al d. Br e. Ti
Calculate the molar mass for Mg(ClO4)2. A) 223.21 g/mol B) 123.76 g/mol C) 119.52 g/mol D) 247.52 g/mol E) 75.76 g/mol
The Freons are a class of compounds containing carbon, chlorine, and fluorine. While they have many valuable uses, they have been shown to be responsible for depletion of the ozone in the upper atmosphere. In 1991, two replacement compounds for Freons went into production: HFC-134a (CH2FCF3) and HCFC-124 (CHClFCF3). Calculate the molar masses of these two compounds.
How many xenon atoms are contained in 2.36 moles of xenon?
How many moles are in 26.7 grams of calcium nitrate?
How many argon atoms are contained in 7.66 x 10 5 mol of argon? A) 4.61 × 1029 Ar atoms B) 1.84 × 1028 Ar atoms C) 1.15 × 1028 Ar atoms D) 7.86 × 1020 Ar atoms E) 3.24 × 1026 Ar atoms
Calculate the mass, in kg, of each sample. a. 7.55 x 1026 cadmium atoms b. 8.15 x 1027 nickel atoms c. 1.22 x 1027 manganese atoms d. 5.48 x 1029 lithium atoms
How many helium atoms are there in a helium blimp containing 536 kg of helium?
If the mass of 2.51 x 10 -3 moles of compound A is 0.452 g, then what is the molar mass?
Calculate the average mass, in grams, of one platinum atom.
Using scanning tunneling microscopy, scientists at IBM wrote the initials of their company with 35 individual xenon atoms (as shown below). Calculate the total mass of these letters in grams.
How many Li atoms are contained in 97.9 g of Li? A) 5.90 × 1025 Li atoms B) 7.09 × 1021 Li atoms C) 8.49 × 1024 Li atoms D) 4.27 × 1022 Li atoms E) 4.18 × 1024 Li atoms
How many iron atoms are contained in 354 g of iron? A) 2.62 × 1025 Fe atoms B) 2.13 × 1026 Fe atoms C) 4.69 × 1024 Fe atoms D) 3.82 × 1024 Fe atoms E) 9.50 × 1022 Fe atoms
How many formula units are in 0.25 mole of Na 2O? A)  4.5 x 1023    B)  0.75                  C)  1.5 x 1023    D)  4.2 x 10–25    E)  0.25
Phosphorus tribromide is a liquid with a density of 2.852 g/cm3.  A beaker contains 0.4875 moles of this compound.    a)  What is the chemical formula of phosphorus tribromide?   b) What is the volume of liquid in milliliters (mL)? c)  How many molecules of phosphorus tribromide are in the beaker? d)  How many atoms of bromine are in the beaker?
If 4.05 x 1023 molecules of a substance have a mass of 86.2 g, what is the molar mass of the substance? A)  128 g/mol B)  3.49 x 1025 g/mol                                    C)  2.13 x 1022 g/mol D)  4.70 x 1021 g/mol           E)  58.0 g/mol
A 1.000-g sample of a metal chloride, MCl 2, is dissolved in water and treated with excess aqueous silver nitrate. After drying, the silver chloride that formed weighed 1.286 g. Calculate the atomic mass of M.   a) 222.8 g b) 76.00 g c) 152.0 g d) 304.0 g e) none of these 
An α particle,  4H2+, has a mass of 4.00151 amu. Find the value of its charge-to-mass ratio in C/kg.  
Suppose we have 100 g of each of the following substances. Which sample contains the largest number of moles? 1. MgCO3, formula weight 84.3 2. AgCl, formula weight 143.3 3. Impossible to tell, unless we know what reaction will take place with the substance. 4. HCl, formula weight 36.5 5. H2 O, formula weight 18.0
What mass of the compound CrO3 (M = 100.0) contains 4.5 x 10 23 oxygen atoms? a) 2.25 g b) 12.0 g c) 25.0 g d) 75.0 g
A penny has a thickness of approximately 1.0 mm. If you stacked Avogadro's number of pennies one on top of the other on Earth's surface, how far would the stack extend (in km)? [For comparison, the sun is about 150 million km from Earth and the nearest star (Proxima Centauri) is about 40 trillion km from Earth.]
Identify the correct statement regarding the mole. a) A mole of oxygen gas contains 6.02 x 10 23 atoms. b) A mole of chlorine gas contains 2 x 6.02 x 10 23 molecules. c) A mole of carbon dioxide contains two moles of oxygen atoms. d) A mole of ammonia gas (NH 3) has a mass of 34.0 g. e) A mole consists of the number of particles in exactly 12 g of naturally occurring carbon. 
Consider the stack of pennies in the previous problem. How much money (in dollars) would this represent? If this money were equally distributed among the world's population of 6.5 billion people, how much would each person receive? Would each person be a millionaire? Billionaire? Trillionaire? 
How many moles of water contain 2.22 x 10 24 molecules of water? (A) 3.69 moles (B) 0.272 moles (C) 2.72 moles (D) 36.9 moles (E) 1.34 x 1048 moles
 A pure titanium cube has an edge length of 2.78 in. How many titanium atoms does it contain? Titanium has a density of 4.50 g/ cm3. 
Calculate the mass in grams of 1.505 x 10 23 molecules of CH 4. (A) 4 g (B) 16 g (C) 40 g (D) 64 g (E) 2.4 x 1024 g
Calculate the molar mass for Mg(ClO4)2. A) 247.52 g/mol B) 119.52 g/mol C) 123.76 g/mol D) 223.21 g/mol E) 75.76 g/mol
How many fluorine atoms are present in 19.75 g of the Freon C 2HBrClF3? (A) 1.81 x 1023 (B) 6.02 x 1023 (C) 6.69 x 1021 (D) 6.03 x 1022 (E) 2.23 x 1023
6.02 x 10 21 molecules of an unknown substance X has a mass of 2.00 grams. What is the molar mass of X in g/mole? (A) 0.02 g/mol (B) 0.2 g/mol (C) 20 g/mol (D) 200 g/mol (E) 2000 g/mol
How many bromide ions are in 0.55 g of iron(III) bromide? HINT: What does the Roman numeral mean? a. 1.1 x 1021 ions b. 3.4 x 1021 ions c. 3.3 x 1023 ions d. 9.9 x 1023 ions e. 2.9 x 1026 ions
How many Cl atoms are there in 27.3 grams of magnesium chloride?  
A 67.2 g sample of a gold and palladium alloy contains 2.49 x 10 23 atoms. What is the composition (by mass) of the alloy? 
How many Cl– ions are there in 15.6 g of MgCl 2?
How many N2O4 molecules are contained in 76.3 g N 2O4? The molar mass of N2O4 is 92.02 g/mol. A) 4.59 × 10 25 N2O4 molecules B) 5.54 × 10 25 N2O4 molecules C) 7.26 × 10 23 N2O4 molecules D) 1.38 × 10 24 N2O4 molecules E) 4.99 × 10 23 N2O4 molecules
What is the mass of 4.50 x 1022 atoms of magnesium, Mg? (A) 0.0748 g (B) 0.182 g (C) 0.897 g (D) 1.82 g (E) 18.2 g
Calculate the number of moles in 55.0 g of magnesium hydroxide. (A) 0.943 mol (B) 1.33 mol (C) 1.83 mol (D) 2.89 mol (E) 5.68 x 1023 mol
How many  C2H4  molecules are contained in 45.8 mg of  C 2H4 ? The molar mass of  C2H4  is 28.05 g/mol. A) 2.71× 10 20 C2H4 molecules B) 9.83 × 10 20  C2H4  molecules C) 7.74 × 10 26  C2H4  molecules D) 4.69 × 10 23  C2H4 molecules E) 3.69 × 10 23  C2H4  molecules
What is the molecular weight of glucose, C6H12O6
32.0 grams of the element oxygen: (A) contain 6.02 x 1023 atoms of oxygen (B) contain 1.204 x 1024 molecules of oxygen (C) contain the same number of oxygen atoms as 18.0 g of water (D) contain the same number of oxygen atoms as 72.0 g of water (E) contain the same number of oxygen atoms as 90.0 g of water
Calculate the number of nitrogen atoms in 240. g of ammonium nitrate. (A) 2.01 x 1023 nitrogen atoms (B) 6.02 x 1023 nitrogen atoms (C) 1.20 x 1024 nitrogen atoms (D) 1.81 x 1024 nitrogen atoms (E) 3.61 x 1024 nitrogen atoms
6.02 x 1021 molecules of an unknown substance X has a mass of 11.0 grams. What is the molar mass of X in g/mole? (A) 110 g/mol (B) 220 g/mol (C) 1100 g/mol (D) 2200 g/mol (E) cannot be determined without the formula of X
How many oxygen atoms are in a 125 mg sample of aspirin? The molar mass of aspirin is 180.15 g/mol and its molecular formula is C9H8O4.   a) 4.18 × 1023 b) 4.18 × 1020 c) 1.67 × 1021 d) 1.36 × 1025 e) 8.68 × 1023
How many moles are in 42.6 g of water? 1. 767 mol 2. 3.04 mol 3. 2.66 mol 4. 2.37 mol
Of the following: one atom of uranium (U), one molecule of benzene (C6 H6), one mole of hydrogen atoms, or 6.02 × 1020 oxygen molecules, which one weighs the most? 1. one mole of hydrogen atoms 2. 6.02 × 1020 oxygen molecules 3. one molecule of C6 H6 4. one atom of U
What is the mass (in kg) of 6.89 × 10 25 molecules of CO2? The molar mass of CO2 is 44.01 g/mol. A) 5.04 kg B) 3.85 kg C) 3.03 kg D) 2.60 kg E) 6.39 kg
What is the mass of 9.44 × 10 24 molecules of NO2? The molar mass of NO2 is 46.01 g/mol. A) 294 g B) 341 g C) 205 g D) 685 g E) 721 g
In Section 2.9, it was stated that 1 mol of sand grains would cover the state of Texas to several feet. Estimate how many feet by assuming that the sand grains are roughly cube-shaped, each one with an edge length of 0.10 mm. Texas has a land area of 268,601 square miles. 
How many moles of N2O3 contain 2.55 × 1024 oxygen atoms? A) 7.87 moles N2O3  B) 1.41 moles N2O3  C) 4.23 moles N2O3  D) 12.7 moles N2O3  E) 2.82 moles N2O3 
How many moles of C3H8 contain 4.95 × 10 24 hydrogen atoms? A) 3.09 moles C3H8 B) 6.58 moles C3H8 C) 1.03 moles C3H8 D) 9.73 moles C3H8 E) 8.22 moles C3H8
What is the molar mass of calcium permanganate? A) 199 g/mol B) 278 g/mol C) 216 g/mol D) 159 g/mol
How many sulfur atoms are present in 256 mg of Al 2(S2O3)3? a. 3.95 x 1022 b. 6 c. 7.90 x 1022 d. 0.393 e. 2.37 x 1021
What is the identity of substance X if 0.380 mol of X weighs 17.5 g? A) NO2 B) N2O C) N2O4 D) NO3
How many sodium atoms are in 6.0 g of Na 3N? a. 1.3 x 1023 atoms b. 3.6 x 1024 atoms c. 1.217 atoms d. 4.6 x 1022 atoms e. 0.072 atoms
A 2.000 g sample of an unknown metal, M, was completely burned in excess O 2 to yield 0.02224 mol of the metal oxide, M2O3. What is the metal? A. Y B. Ca C. Al D. Sc
How many atoms of carbon are there in 0.80 moles of C 6H4Cl2? a. 3.9 x 1024 b. 3.6 x 1024 c. 2.9 x 1024 d. 6.0 x 1023 e. 4.8 x 1023
How many sulfur atoms are there in 3.8 mol of sulfur? 
Which of the following samples contains the largest number of atoms? a. 1 g Li b. 1 g F2 c. 1 g C d. 1 g P4 e. 1 g N2
How many moles of aluminum do 5.8 X 1024 aluminum atoms represent?
What is the average mass in grams of one atom of iron? a. 55.85 g b. 6.02 x 10-23 g c. 9.28 x 10-23 g d. 1.66 x 10-24 g e. 55.85 x 10-25 g
Determine the number of moles of silicon in 5.00 mg Si. a. 1.78 x 10-4 mol b. 2.40 x 10-4 mol c. 0.140 mol d. 5.62 mol e. 5.62 x 103 mol
What mass of carbon is present in 0.500 mol of sucrose (C12H22O11)? Molar mass: C12H22O11 = 342 g/mol A. 60.0 g B. 72.0 g C. 90.0 g D. 120 g  
What mass of carbon is present in 0.500 mol of sucrose (C 12H22O11)? a) 60.0 g  b) 72.0 g c) 90.0 g d) 120.0 g
How many atoms are in 1.50 g of Al? a) 0.0556 b) 18.0 c) 3.35 x 1022 d) 2.44 x 1025
A 7.36-g sample of copper is contaminated with an additional 0.51 g of zinc. Suppose an atomic mass measurement was performed on this sample. What would be the measured atomic mass?
How many grams of gold contain 1.39 x 10 23 atoms of gold? a. 0.220 g b. 0.231 g c. 4.33 g d. 45.5 g e. 853 g
What mass of carbon is present in 1.4 x 10 20 molecules of sucrose (C12H22O11)? a) 1.7 x 1021 g b) 2.0 x 1022 g c) 3.3 x 10 -2 g d) 2.8 x 10-3 g
A 0.370 mol sample of a metal oxide (M 2O3) weighs 55.4 g. How many grams of M are in the sample, and what element is represented by the symbol M? a) 75.28 g/mol; Arsenic b) 101.7 g; Ruthenium c) 37.6 g; Vanadium d) 17.8 g; Metalium e) 41.3 g; Iron
How many atoms of oxygen are there in 53.2 g Al 2(SO4)3?       a. 9.36 x 1022 b. 3.75 x 1023 c. 1.12 x 1024 d. 2.81 x 1023
What mass (in kg) does 0.0822 moles of lead (Pb) have? a. 0.397 kg b. 17.0 kg c. 2.52 kg d. 0.0170 kg e. 0.632 kg
Which of the following amounts would contain the  least atoms?  a) 10.0 g Sr b) 10.0 g Br c) 10.0 g Mg d) 10.0 g Li
A 1.000-g sample of a metal chloride, MCl 2, is dissolved in water and treated with excess aqueous silver nitrate.  After drying, the silver chloride that formed weighed 1.286 g. Calculate the mass of M.  a) 222.8 g     b) 76.00g      c) 152.0 g      d) 304.0 g      e) none of these
Phenylenediamine (pictured below) is mainly used as a component of engineering polymers and composites. It is also an ingredient in hair dyes and is occasionally used as a substitute for henna. What mass of phenylenediamine contains 45.0 g carbon? a. 67.6 g b. 45.0 g c. 72.0 g d. 100 g
Phenylenediamine (pictured below) is mainly used as a component of engineering polymers and composites. It is also an ingredient in hair dyes and is occasionally used as a substitute for henna. How many molecules are in a 2.00 g of phenylenediamine? a. 1.30 x 1028 b. 1.11 x 1022 c. 3.59 x 10-20 d. 3.07 x 10-24
A sample of a compound of xenon and fluorine contains molecules of a single type; XeFn , where n is a whole number. If 9.03 x 10 20 of these XeFn molecules have a mass of 0.311 g, what is the value of n? a) 2 b) 3 c) 4 d) 6
Which of the following amounts have the  most molecules?  a) 15.0 g N2 b) 15.0 g Br2 c) 15.0 g O2 d) 15.0 g l2
If 2.50 grams of an unknown compound contains 6.25 x 10 19 molecules, what is its molecular mass?   
How many Cl atoms are there in 27.3 grams of magnesium chloride?
A 3.41 x 10–6 g sample of a compound is known to contain 4.67 x 10 16 molecules. This compound is a) CO2 b) CH4 c) NH3 d) H2O
What is the molar mass of aspartic acid, C 4O4H7N?  A) 43.03 g/mol B) 70.02 g/mol C) 86.91 g/mol D) 133.11 g/mol      E) 197.98 g/mol
The number of atoms in 9.0 g of aluminum is the same as the number of atoms in  a) 8.1 g of magnesium. b) 9.0 g of magnesium. c) 12.1 g of magnesium. d) 18.0 g of magnesium.
A single molecule of a certain compound has a mass of 3.4 x 10 –22 g. Which value comes closest to the mass of a mole of this compound? a) 50 g•mol–1 b) 100 g•mol–1 c) 150 g•mol–1 d) 200 g•mol–1
What mass of KClO3 will produce 48.0 g of oxygen gas, O2, if the decomposition of KClO3 is complete? a) 61.3 g b) 74.5 g c) 122.5 g d) 245.0 g
What mass of aluminum bromide will contain 6.3 x 10  20 bromide ions ? a) 93 mg b) 31 mg c) 9.3 mg d) 27 mg e) 273 mg
Amavadin is a vanadium-containing compound found in three species of toxic mushrooms. The chemical formula for amavadin is VC12H16N2O10 and has molar mass 398.94 g•mol-1. If a mushroom contains 2.00 mg of amavadin, how many molecules are present? a. 1.20 x 1023 b. 4.80 x 1023 c. 3.02 x 1021 d. 3.02 x 1018  
Determine the volume of hexane that contains 5.33 x 10 22 molecules of hexane. The density of hexane is 0.6548 g/mL and its molar mass is 86.17 g/mol. a. 8.59 mL b.13.5 mL c. 7.40 mL d. 12.4 mL e. 11.6 mL
What is the mass (grams) of 4.91 x 1021 Pt    atoms?    1 mol Pt = 195.08 g = 6.022 x 1023 atoms
How many sodium ions are contained in 99.6 mg of Na  2SO3 ? a) 1.05 X 1021 b) 1.52 X 1027 c) 2.10 X 1021 d) 9.52 X 1020  
How many moles of Ar are in 5.22 X 1022 atoms of this noble gas?  
Which of the following equals the number of hydrogen atoms in 40 grams of methane? a. 1.5 x 10 24 b. 2.4 x 10 24 c. 6.0 x 10 24 d. 6.022 x 10 23
If 2.50 grams of an unknown compound contains 6.25 x 1019 molecules, what is its molecular mass? 
What mass (in kg) does 5.84 moles of Titanium (Ti) have? a. 0.352 kg b. 0.122 kg c. 0.820 kg d. 0.280 kg e. 0.632 kg
How many moles of methanol are present in a 150.0 gram sample of methanol, CH3OH? a. 7.776 x 10 -24 moles b. 4.681 moles c. 5.172 moles d. 4806 moles e. 2.818 x 10 24 moles
What is the molar mass of calcium phosphate, Ca 3(PO4)2? a. 87.05 g/mol b. 215.21 g/mol c. 278.18 g/mol d. 279.21 g/mol e. 310.18 g/mol
One molecule of a compound weighs 2.03 x 10 -22 grams. Calculate the molar mass of this molecule. a. 3.37 x 10-46 g/mol b. 3.36 x 10-23 g/mol c. 1.23 x 10-21 g/mol d. 1.22 x 10 2 g/mol e. 1.21 x 1024 g/mol
The definition of the mole gives the relationship between: a. mass and the atomic number. b. mass and number of atoms. c. mass and weight. d. the masses of the different isotopes of an atom. e. the isotopes of an atom and the number of atoms.
We have a 1.3 x 1022 lead atoms and the same number of gold atoms. Which statement is true regarding the mass of these samples? a. The mass of both of the samples is the same b. The mass of the lead sample is greater than the mass of the gold sample. c. The mass of the gold sample is greater than the mass of the lead sample. d. The mass of the gold sample is 4.5 g. e. The mass of the lead sample is 4.3 g.
For a 90.0 g sample of glucose (C6H12O6) and a 171.1 g sample of sucrose (C12H22O11), which statement is true? a. The sample of glucose has more moles than the sample of sucrose. b. The sample of sucrose has more moles than the sample of glucose. c. The samples have the same number of moles. d. 1 mol of glucose has greater molecular mass than 1 mol of sucrose. e. 1 mol of glucose has more C atoms in comparison to 1 mol of sucrose.
How many moles are in 25 mg of O 2? (Atomic mass of O = 16.00 g/mol) A) 7.8 ×10−4 B) 1.6 ×10−3 C) 0.40 D) 0.80 E) 800
Which contains the largest number of carbon atoms? A. 0.10 mol of carbon atoms B. 1.2 g carbon C. 0.10 mol of CH4 D. 1.6 g of CH4 E. All are the same
Which of the following contains most hydrogen atoms in one gram of sample? A. HClO4 B. HClO3 C. HClO2 D. HClO E. HCl
A 20.0 g sample of an element contains 4.95 x 1023 atoms. Identify the element. A) Cr B) O C) Mg D) Fe
A compound has a formula of Y2O5. If 2.8 g of Y combines with 8.0 g of oxygen, what is the atomic weight of Y? A. 10 B. 12 C. 14 D. 16 E. 18
What is the mass of one molecule of C8H18 (octane) in grams? A. 114 B. 1.9 x 10-22 C. 26 D. 6.9 x 10-21 E. 3.8 x 10-22
What is A, if 64.0 g of A combines exactly with 142 g of Cl to give the compound ACl 2? A. Br B. Mg C. Ca D. S E. Ba
What is the atomic weight of an element, X, if 1.00g of X combines with 0.66 g of oxygen to form a compound XO3? A. 24 B. 67 C. 73 D. 100 E. 146
A quantity of N2 occupies 62.2 L at a particular temperature and pressure. Its density is 0.900 g/L. How many moles of N2 are in the container? 1. 10.1 mol 2. 12.4 mol 3. Cannot be determined 4. 2.00 mol  5. 34.6 mol
Calcium fluoride is used to fluoridate drinking water. Calculate its molar mass in g/mol. (A) 118.15 (B) 99.15 (C) 78.07 (D) 59.08 (E) 38.00
Calculate the average mass, in grams, of an O2 molecule. a. 32.0 b. 2.00 c. 2.66 x 10-23 d. 1.88 x 10-22 e. 5.31 x 10-23
What is the mass, in grams, of each elemental sample? a. 2.3 x 10 –3 mol Sb
How many xenon atoms are contained in 2.36 moles of xenon?A) 1.87 × 10 26 xenon atomsB) 3.92 × 10 24 xenon atomsC) 1.42 × 10 24 xenon atomsD) 2.55 × 10 23 xenon atomsE) 7.91 × 10 25 xenon atoms
Calculate the molar mass of sodium chloride, NaCl (from the periodic table Na = 22.99 and Cl = 35.45).a) 6.745 g/moleb) 58.44 g/molec) 74.55 g/moled) 67.45 g/molee) 19.00 g/mole
What is the average mass of a single silicon atom in grams?
How many moles of Kr are contained in 398 mg of Kr?     A) 4.75 × 10 -3 moles KrB) 1.19 × 10 -4 moles KrC) 2.99 × 10 -3 moles KrD) 33.4 moles KrE) 2.11 × 10 -4 moles Kr
How much does one sucrose molecule weigh in grams?
How many oxygen molecules are present in a 32.00 g sample of oxygen gas?A. 1 oxygen moleculeB. 4.133 x 1024 oxygen moleculesC. 1.204 x 1024 oxygen moleculesD. 6.022 x 1023 oxygen moleculesE. 2.240 x 1025 oxygen molecules
How many iron atoms are contained in 354 g of iron?     A) 9.50 × 1022 Fe atomsB) 2.13 × 1026 Fe atomsC) 3.82 × 1024 Fe atomsD) 2.62 × 1025 Fe atomsE) 4.69 × 1024 Fe atoms
Calculate the molar mass of Cl 2 if 1.27 x 1022 molecules of gaseous Cl 2 have a mass of 1.5g.
How many molecules are contained in the 254 grams of CH 4? The molar mass of CH4 is 16 grams/mole.
How many Li atoms are contained in 97.9 g of Li?A) 8.49 × 10 24 Li atomsB) 5.90 × 10 25 Li atomsC) 4.27 × 10 22 Li atomsD) 4.18 × 10 24 Li atomsE) 7.09 × 1021 Li atoms
How many silver atoms are there in 3.78 g of silver?
What is the molar mass of aspartic acid, C4O4­H7N?A) 43.03 g/mol     B) 70.56  g/mol                C) 133.11 g/mol               D) 197.11 g/molE) 206.33 g/mol
How many atoms of nickel (Ni) are contained in 47.6 g of Ni?A) 1.23 × 1023 Ni atomsB) 2.87 × 1024 Ni atomsC) 2.96 × 1023 Ni atomsD) 4.88 × 1023 Ni atomsE) 7.43 × 1023 Ni atoms
Calculate the mass (in g) of 1.9 x 10 24 atoms of Pb.A) 2.4 × 10 2 gB) 6.5 × 10 2 gC) 3.2 × 10 2 gD) 1.5 × 10 2 gE) 3.9 × 10 2 g
A student uses a mass balance to dispense 2.05 g of sulfur. How many moles of sulfur is this?A. 0.0639B. 65.7C. 0.0152D. 15.6
Calculate the molar mass of potassium hydroxide (KOH).
How many moles (or molecules or formula units) are in each sample? a. 20.0 g NO2b. 1.35 kg CO2c. 40.4 g KNO3d. 102.3 kg Na2SO4
How many molecules (or formula units) are in each sample?a. 52.03 g CCl4b. 73.85 kg NaHCO3c. 123.22 g C4H10d. 3.15 × 104 g Na3PO4
If you have 20.0 g of carbon dioxide gas, how many molecules of CO 2 do you have?A) 4.30 x 1023 molecules of CO2B) 2.74 x 1023 molecules of CO2C) 5.30 x 1026 molecules of CO2 D) 1.46 x 10-21 molecules of CO2 E) 7.55 x 10-25  molecules of CO2
What is the molar mass of calcium phosphate, Ca 3(PO4)2?
If you had a mol of U.S. dollar bills and equally distributed the money to all of the people of the world, how rich would every person be? Assume a world population of 6 billion.
If you had a mole of U.S. dollar bills and equally distributed the money to all of the people of the world, how rich would every person be? Assume a world population of 7 billion.
A salt crystal has a mass of 0.12 mg. How many NaCl formula units does it contain? 
Determine the number of moles of oxygen atoms in each of the following: 4.49 mol H2O22.17 mol N2O2.33 × 10−2 mol H2CO324.3 mol CO2
What is the mass, in grams, of 1.24 mol of water, H 2O? Express the mass in grams to three significant figures.
Choose the correct value for the total number of molecules in 5 g of sodium carbonate. Choose one answer.a. 7.26 x 1022b. 3.63 x 1022c. 6.02 x 1023d. 82.99
How many moles of hydrogen atoms are in 1.00 mole of C 5H8 molecules?A) 0.25 mol H atomsB) 1.00 mol H atomsC) 5.00 mol H atomsD) 8.00 mol H atomsE) 16.00 mol H atoms
Calculate the mass of 500. atoms of iron (Fe).
What is the molar mass of aspirin, C9H8O4?
What number of Fe atoms and what amount (moles) of Fe atoms are in 500.0 g of iron?
Diamond is a natural form of pure carbon. What number of atoms of carbon are in a 1.00-carat diamond (1.00 carat = 0.200 g)?
What mass (in kg) does 5.84 moles of vanadium (V) have?A) 0.352 kgB) 0.297 kgC) 0.820 kgD) 287 kgE) 2.97 x 103 kg
A diamond contains 5.0 x 10 21 atoms of carbon. What amount (moles) of carbon and what mass (grams) of carbon are in this diamond?
Calculate the mass (in ng) of 2.33 x 1020 atoms of oxygen.a. 3.73 x 106 ngb. 2.25 x 103 ngc. 1.62 x 107 ngd. 4.69 x 107 nge. 6.19 x 106 ng
Calculate the molar mass of the following substances.
Calculate the molar mass of the following substances.b. Ca 3(PO4)2
a. How many moles of atoms are in 8.00 g of 13C?b. Based on your answer in Part A, calculate the number of atoms in this amount of 13C?c. Based on your answer in Part B, how many electrons are in this amount of 13C?d. Based on your answer in Part B, how many neutrons are in this amount of 13C?
How many moles (of molecules or formula units) are in each sample?a. 62.20 g CF2Cl2b. 21.3 kg Fe(NO3)2c. 0.1911 g C8H18d. 130 kg CaO
Calculate the molar mass of the following substances.c. Na 2HPO4
Determine the number of moles of aluminum in 96.7 g of Al.A. 0.279 mol  B. 3.58 mol    C. 7.43 mol    D. 4.21 mol    E. 6.02 x 1023 mol
How many C atoms are in 5.50 g of C?A. 5.01 x 1022 C atomsB. 3.31 x 1024 C atomsC. 6.02 x 1023 C atomsD. 2.76 x 1023 C atomsE. 5.50 x 1023 C atoms
Monel metal is a corrosion-resistant copper-nickel alloy used in the electronics industry. A particular alloy with a density of 8.80 g/cm3 and containing 0.090 % Si by mass is used to make a rectangular plate that is 15.0 cm long, 12.5 cm wide, and 3.50 mm thick and has a 2.50-cm-diameter hole drilled through its center such that the height of the hole is 3.50 mm .The silicon in the plate is a mixture of naturally occurring isotopes. One of the those isotopes is silicon-30, which has an atomic mass of 29.97376 amu. The percent natural abundance, which refers to the atoms of a specific isotope, of silicon-30 is 3.10%.a. What is the volume of the plate?b. How many silicon-30 atoms are found in this plate?
Silver chloride, often used in silver plating, contains 75.27% Ag.Calculate the mass of silver chloride required to plate 225 mg of pure silver.
How many chloride ions are present in 0.100 mol of MgCl  2?A)  0.200 Cl– ionsB)  6.02 ´ 1022 Cl– ionsC)  1.20 ´ 1023 Cl– ionsD)  3.32 ´ 10–25 Cl– ionsE)  3.01 ´ 1024 Cl– ions
How many molecules of ethanol (C2H5OH) (the alcohol in alcoholic beverages) are present in 145 mL of ethanol? The density of ethanol is 0.789 g/cm3.
How many oxygen atoms are present in 1.50 mol of Zn(NO 3)2?A)  4.50 atomsB)  9.00 atomsC)  9.03 ´ 1023 atomsD)  5.42 ´ 1024 atomsE)  1.49 ´ 10–23 atoms                            
A drop of water has a volume of approximately 0.05 mL. How many water molecules does it contain? The density of water is 1.0 g/cm3. 
How many grams are present in 6.5 moles of Cu(NO 3)2?a. 1220 gb. 404 gc. 1080 gd. 986 g
Glucose is the type of sugar the human body metabolizes to produce energy. Calculate the formula mass of glucose, C6H12O6.a. 220.02 amub. 340.00 amuc. 180.18 amu
If the molar mass of a substance is 44.01 g/mol, what is the mass of 1.05 x 10 24 molecules of the substance?A)  76.7 g   B)  1.74 g   C)  4.62 x 1025 g   D)  4.19 x 10–23 g   E)  25.2 g
What is molar mass of Na 2CO3?
A chemical reaction requires 6.00 moles of Fe(NO3)3. What mass of iron(III) nitrate is needed?A)  24.3 g   B)  875 g   C)  40.3 g               D)  1.45 x 103 g                E)  515 g
A gold cylinder has a length of 6.25 cm and a radius of 1.25 cm. The density of gold is 19.3 g/cm3. Vcylinder = π r 2 lHow many gold atoms are contained in the gold cylinder?A. 1.94 x 10 -19 atomsB. 1.81 x 10 24 atomsC. 1.92 x 10 21 atomsD. 9.85 x 10 23 atoms
Which of the following contains the FEWEST atoms? You shouldnʹt need to do a calculation here.A) 4.0 g LiB) 4.0 g NaC) 4.0 g RbD) 4.0 g KE) 4.0 g Ca
Determine the number of moles of oxygen atoms in each sample:a. 4.88 mol H2O2b. 2.15 mol N2Oc. 0.0237 mol H2CO3d. 24.1 mol CO2
Precious metals are sometimes weighed in old-timey units like “troy ounces”, where 1 troy ounce = 31.1035 grams.  A platinum coin is made that weighs 0.5003 troy ounces.  The coin has a radius of 13.5 mm and a thickness of 1.28 mm.  (Useful information: volume of a cylinder = (π r2)h  where r is radius, and h is height or thickness)a) What is its density, in g/cm3?      b) How many atoms of platinum are in the coin?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O.a. What is the molar mass of bauxite?
A Freon leak in the air-conditioning system of a large building releases 12 kg of CHF2Cl per month. If the leak is allowed to continue, how many kilograms of Cl will be emitted into the atmosphere each year?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O.b. What is the mass of aluminum in 0.58 mol bauxite?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O.c. How many atoms of aluminum are in 0.58 mol bauxite?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O.d. What is the mass of 2.1 x 10 24 formula units of bauxite?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O. The • H2O in the formula are called waters of hydration. Each formula unit of the compound contains two water molecules.a. What is the molar mass of bauxite?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O. The • H2O in the formula are called waters of hydration. Each formula unit of the compound contains two water molecules.b. What is the mass of aluminum in 0.58 mole of bauxite?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O. The • H2O in the formula are called waters of hydration. Each formula unit of the compound contains two water molecules.c. How many atoms of aluminum are in 0.58 mole of bauxite?
Bauxite, the principal ore used in the production of aluminum, has a molecular formula of Al2O3 • 2H2O. The • H2O in the formula are called waters of hydration. Each formula unit of the compound contains two water molecules.d. What is the mass of 2.1 x 10 24 formula units of bauxite?
Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).a. CF2Cl2
Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).b. CFCl3
The molecular formula of acetylsalicylic acid (aspirin), one of the most commonly used pain relievers, is C9H8O4. a. Calculate the molar mass of aspirin.
Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).c. C2F3Cl3 
The molecular formula of acetylsalicylic acid (aspirin), one of the most commonly used pain relievers, is C9H8O4. b. A typical aspirin tablet contains 500. mg of C 9H8O4. What amount (moles) of C9H8O4 molecules and what number of molecules of acetylsalicylic acid are in a 500.-mg tablet?
A sample mercury has a volume of 0.50 mL and a mass of 6.765 ga) What is the density of the material in mg/mL? b) How many atoms are in this 0.50 mL sample of mercury?  
Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).d. CF3Cl
What amount (moles) is represented by each of these samples?a. 20.0 mg caffeine, C8H10N4O2
What amount (moles) is represented by each of these samples?b. 2.72 x 10 21 molecules of ethanol, C2H5OH
Calculate the mass of 2.25 x 1022 tungsten atoms. Express the mass in grams to three significant figures.
How many of the indicated atoms are represented by each chemical formula: (a) carbon atoms in C2H5COOCH3
What amount (moles) is represented by each of these samples?c. 1.50 g of dry ice, CO 2
How many of the indicated atoms are represented by each chemical formula: (b) oxygen atoms in Ca(ClO4)2
What number of atoms of nitrogen are present in 5.00 g of each of the following?a. glycine, C2H5O2N
What mass (in kg) does 5.84 moles of potassium (K) have?A) 0.352kgB) 0.228kgC) 0.820kgD) 0.280kgE) 0.632kg
How many of the indicated atoms are represented by each chemical formula: (c) hydrogen atoms in (NH4)2HPO4?
What number of atoms of nitrogen are present in 5.00 g of each of the following?b. magnesium nitride
What number of atoms of nitrogen are present in 5.00 g of each of the following?c. calcium nitrate
What number of atoms of nitrogen are present in 5.00 g of each of the following?d. dinitrogen tetroxide
How many molecules of N2O4 are in 76.3 g N2O4? The molar mass of N2O4 is 92.02 g/mol.a. 5.54 x 1025 N2O4 moleculesb. 7.26 x 1023 N2O4 moleculesc. 1.38 x 1024 N2O4 moleculesd. 4.59 x 1025 N2O4 moleculese. 4.99 x 1023 N2O4 molecules
Calculate the formula mass for each compound. a. MgBr2
Calculate the formula mass for each compound. b. HNO2
How many moles of carbon atoms are present in a piece of diamond which has a volume of 1.00 cm3? The density of diamond is 3.53 g/cm3.
Calculate the formula mass for each compound. c. CBr4
The mass of an average blueberry is 0.75 g and the mass of an automobile is 2.0 X 103 kg. Find the number of automobiles whose total mass is the same as 1.0 mol blueberries.
Calculate the formula mass for each compound. d. Ca(NO3)2
How many moles of atoms are in 7.00g of 13C?
What is the mass (in kg) of 6.89 × 10 25 molecules of CO2? The molar mass of CO2 is 44.01 g/mol.A) 2.60 kgB) 6.39 kgC) 5.04 kgD) 3.03 kgE) 3.85 kg 
Calculate the error for the molar mass of acetic acid, CH 3CO2H. The atomic masses for each element are C = 12.0106 ± 0.0010, H = 1.00798 ± 0.00014, and O = 15.9990 ± 0.0008
In eukaryotes, when mature mRNA is hybridized to complementary DNA, _______.a. introns loop out as single-stranded regions of DNA b. exons loop out as single-stranded regions of DNA c. introns loop out as single-stranded regions of RNA d. exons loop out as single-stranded regions of RNA
Chloral hydrate (C2H3Cl3O2) is a drug formerly used as a sedative and hypnotic. It is the compound used to make “Mickey Finns” in detective stories.a. Calculate the molar mass of chloral hydrate.
Chloral hydrate (C2H3Cl3O2) is a drug formerly used as a sedative and hypnotic. It is the compound used to make “Mickey Finns” in detective stories.b. What amount (moles) of C2H3Cl3O2 molecules are in 500.0 g chloral hydrate?
Chloral hydrate (C2H3Cl3O2) is a drug formerly used as a sedative and hypnotic. It is the compound used to make “Mickey Finns” in detective stories.c. What is the mass in grams of 2.0 x 10 –2 mol chloral hydrate?
Your car is 4.48 metric tons. How many times more massive is your car than an aluminum (Al) atom?
How many moles (of molecules or formula units) are in each sample?a. 55.98 g CF2Cl2
Chloral hydrate (C2H3Cl3O2) is a drug formerly used as a sedative and hypnotic. It is the compound used to make “Mickey Finns” in detective stories.d. What number of chlorine atoms are in 5.0 g chloral hydrate?
How many moles (of molecules or formula units) are in each sample?b 23.6 kg Fe(NO3)2
A pure copper sphere has a radius of 0.935 in. How many copper atoms does it contain? [The volume of a sphere is (4/3)πr 3 and the density of copper is 8.96 g/ cm 3.]  
How many moles (of molecules or formula units) are in each sample?c. 0.1187 g C8H18
Chloral hydrate (C2H3Cl3O2) is a drug formerly used as a sedative and hypnotic. It is the compound used to make “Mickey Finns” in detective stories.f. What is the mass of exactly 500 molecules of chloral hydrate?
How many atomic mass units is 1 mole of water? 
Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.a. What is the molar mass of dimethylnitrosamine?
Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.b. How many moles of (CH3)2N2O molecules are present in 250 mg dimethylnitrosamine?
If you drink 225.0 g of pure water, about how many molecules of water do you drink?
How many moles (of molecules or formula units) are in each sample?d. 195 kg CaO
Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.c. What is the mass of 0.050 mol dimethylnitrosamine?
How many moles of water, H2O, contain 2.0 × 1022 molecules of water?
Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.d. How many atoms of hydrogen are in 1.0 mol dimethylnitrosamine?
The molecular mass of sodium oxide (Na 2O) is a. 61.97894b. 45.97954c. 22.98977d. 38.98917
How many molecules are in each sample?a. 6.5 g H2O
Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.e. What is the mass of 1.0 x 10 6 molecules of dimethylnitrosamine?
Determine the molar mass of sodium bicarbonate (from periodic table).molar mass of Na _____ x 1 mol Na = _____molar mass of H _____ x 1 mol H = _____molar mass of C _____ x 1 mol C = _____molar mass of O _____ x 3 mol O =Sum for total molar mass _____
Calculate the mass of 1.00 x 10 24 (a septillion) molecules of water.
Common brass is a copper and zinc alloy containing 37.0% zinc by mass and having a density of 8.48 g/cm3. A fitting composed of common brass has a total volume of 112.5  cm3. How many atoms (copper and zinc) does the fitting contain? 
How many molecules are in each sample?b. 389 g CBr4
Dimethylnitrosamine, (CH3)2N2O, is a carcinogenic (cancer-causing) substance that may be formed in foods, beverages, or gastric juices from the reaction of nitrite ion (used as a food preservative) with other substances.f. What is the mass in grams of one molecule of dimethylnitrosamine?
How many molecules are in each sample?c. 22.1 g O2
How many sodium ions are contained in 99.6 mg of Na2SO3? The molar mass of Na2SO3 is 126.05 g/mol.A) 4.76 × 10 20 sodium ionsB) 2.10 × 10 21 sodium ionsC) 1.52 × 10 27 sodium ionsD) 1.05 × 10 21 sodium ionsE) 9.52 × 10 20 sodium ions
How many grams of P are contained in one mole of Mg  3 (PO4 )2
How many molecules are in each sample?d. 19.3 g C8H10
An ionic compound has the formula MCl2. The mass of 0.3011 mol of the compound is 62.69 grams. What is the identity of the metal? a. Ni b. Cu c. Ba d. Hg e. Sn  
You have 2.50 g of each of the following elements: Ca, Cu, Cs, C, and Cr. Which sample contains the largest number of atoms? a. Ca b. Cu c. Cs d. C e. Cr  
Monel metal is a corrosion-resistant copper-nickel alloy used in the electronics industry. A particular alloy with a density of 8.80 g/cm3 and containing 0.074% Si by mass is used to make a rectangular plate that is 15.0 cm long, 12.5 cm wide, and 4.50 mm thick and has a 2.50 cm diameter hole drilled through its center such that the height of the hole is 4.50 mm.The silicon in the plate is a mixture of naturally occurring isotopes. One of the those isotopes is silicon-30, which has an atomic mass of 29.97376 amu and a percent natural abundance of 3.10%.How many silicon-30 atoms are found in this plate?
A particular brand of beef jerky contains 0.0552% sodium nitrite by mass and is sold in an 8.00-oz bag. What mass of sodium does the sodium nitrite contribute to sodium content of the bag of beef jerky? 
Phosphorus is obtained primarily from ores containing calcium phosphate. If a particular ore contains 57.8% calcium phosphate, what minimum mass of the ore must be processed to obtain 1.00 kg of phosphorus? 
Calculate the oxygen atoms in 25.0g of CaCO3 
What is the mass of a sample of water containing 3.55 x 10  22 molecules of H2O?
The total number of atoms in one formula unit of Fe2(SO4)3 , isa. 5.b. 14.c. 15.d. 17.e. 19.
Calculate the number of phosphorus atoms in  0.5 g of phosphorus.1. 1.31467e+222. 9.72106e+213. 1.45733e+244. 7.1168e+235. 2.91632e+226. 2.01787e+227. 9.38124e+238. 5.06803e+239. 1.10065e+2210. 3.49958e+22
You ate 97.0g of NaCl. How many sodium ions does this quantity of NaCl contain?
Calculate the mass (in g) of each sample.a 4.5 x 1025 O3 molecules.
Each mole of Al(NO3 )3 contains how many moles of oxygen atoms?1. 1 mol2. 6 mol3. 3 mol4. 9 mol 5. 12 mol
Calculate the mass (in g) of each sample.b. 9.85 x 1019 CCl2F2 molecules
Calculate the mass (in g) of each sample.c. 1 water molecule
Calculate the molar mass of Ca 3(PO4)2.A) 215.21 g/molB) 246.18 g/molC) 279.21 g/molD) 87.05 g/molE) 310.18 g/mol
You ate 5.0g of sugar (C6H12O6). This quantity of sugar contains oxygen that is equivalent to how many moles of ozone (O3)?
A sugar crystal contains approximately 1.8 x 1017 sucrose (C12H22O11) molecules. What is its mass in mg?
What mass (in kg) does 5.84 moles of titanium (Ti) have? a. 0.352 kg b. 0.122 kg c. 0.820 kg d. 0.280 kg e. 0.632 kg
Consider the compound C2H4O2. How many grams of oxygen are in 3.0 grams of it?
In the gaseous state, chlorine exists as a diatomic molecule Cl 2 (Molar mass = 70.9 g/mol). Calculate the number of moles of chlorine present in 150  g of chlorine gas.Express the quantity in moles to three significant figures.
How many N2O4 molecules are contained in 76.3 g N 2O4? The molar mass of N 2O4 is 92.02 g/mol.A) 5.54 × 1025 N2O4 moleculesB) 7.26 × 1023 N2O4 moleculesC) 1.38 × 1024 N2O4 moleculesD) 4.59 × 1025 N2O4 moleculesE) 4.99 × 1023 N2O4 molecules
How many C2H4 molecules are contained in 45.8 mg of C 2H4? The molar mass of C2H4 is 28.05 g/mol.A) 9.83 × 1020 C2H4 moleculesB) 7.74 × 1026 C2H4 moleculesC) 2.71× 1020 C2H4 moleculesD) 3.69 × 1023 C2H4 moleculesE) 4.69 × 1023 C2H4 molecules
What is the mass of a single chlorine molecule, Cl 2?A) 35.45 gB) 70.90 gC) 5.887 × 10 -23 gD) 1.177 × 10 -22 g
How many oxygen atoms are there in 3.00 g of sodium dichromate, Na  2Cr2O7?A) 9.85 × 10 20 oxygen atomsB) 0.0801 oxygen atomsC) 6.90 × 10 21 oxygen atomsD) 4.83 × 10 22 oxygen atoms
What is the mass of one molecule of C 8H18 (octane) in grams?A. 114B. 1.9 x 10-22 C. 26D. 6.9 x 10-21 E. 3.8 x 10-22
A Freon leak in the air-conditioning system of an old car releases 25 g of CF 2Cl2. How many molecules of Freon are emitted?a. 1.5 x 1025b. 0.211c. 1.2 x 1023d. 1.8 x 1027
The world population is estimated to be approximately 7 billion people.How many moles of people are there? Express your answer using one significant figure and include the appropriate units. 
How many atoms of oxygen are contained in 47.6 g of Al 2(CO3)3? The molar mass of Al2(CO3)3 is 233.99 g/mol.A) 1.23 × 1023 O atomsB) 2.96 × 1024 O atomsC) 2.87 × 1025 O atomsD) 1.10 × 1024 O atomsE) 3.19 × 1024 O atoms
How many sodium ions are contained in 99.6 mg of Na 2SO3? The molar mass of Na2SO3 is 126.05 g/mol.A) 1.52 × 1027 sodium ionsB) 4.76 × 1020 sodium ionsC) 2.10 × 1021 sodium ionsD) 1.05 × 1021 sodium ionsE) 9.52 × 1020 sodium ions
How many moles of N 2O3 contain 2.55 × 10 24 oxygen atoms?A) 1.41 moles N2O3B) 4.23 moles N2O3C) 12.7 moles N2O3D) 7.87 moles N2O3E) 2.82 moles N2O3
How many moles of C3H8 contain 4.95 × 1024 hydrogen atoms?A) 8.22 moles C3H8B) 6.58 moles C3H8C) 1.03 moles C3H8D) 9.73 moles C3H8E) 3.09 moles C3H8
How many millimoles of Ca(NO3)2 contain 4.78 × 1022 formula units of Ca(NO3)2? The molar mass of Ca(NO3)2 is 164.10 g/mol.A) 12.6 mmol Ca(NO3)2B) 13.0 mmol Ca(NO3)2C) 20.7 mmol Ca(NO3)2D) 79.4 mmol Ca(NO3)2E) 57.0 mmol Ca(NO3)2
How many moles of C3H8 contain 9.25 × 1024 molecules of C3H8?A) 65.1 moles C3H8B) 28.6 moles C3H8C) 34.9 moles C3H8D) 46.2 moles C3H8E) 15.4 moles C3H8
Calculate the molar mass of ammonium phosphate (NH 4)3PO4 to correct sig. fig. 
What is the amount, in moles, of each elemental sample?a. 11.8 g Ar 
How many molecules of ethane are contained in 25.0 mL of butane? The density of butane is 0.6011 g/mL and the molar mass is 58.12 g/mol.A) 2.59 × 1023 molecules butaneB) 1.46 × 1027 molecules butaneC) 6.87 × 1023 molecules butaneD) 1.56 × 1023 molecules butaneE) 7.14 × 1025 molecules butane
What is the amount, in moles, of each elemental sample? b. 3.55 g Zn
What is the amount, in moles, of each elemental sample? c. 26.1 g Ta
An atom of an element weights 9.12 x 10-23 g. What is the atomic mass of this element in atomic mass units?a. 45.0 b. 54.9c. 55.8d. 58.7e. 63.5
Avogadro's number equals the number ofa) atoms in one mole of atoms.b) molecules in one mole of O2.c) marbles in one mole of marbles.d) all of the above.
What is the molar mass of magnesium hydroxide, Mg(OH) 2, a common antacid?(A) 58 g/mol(B) 56 g/mol(C) 42 g/mol(D) 41 g/mol
How many 150-mg aspirin tablets can be made from 15.0 kg of aspirin? a. 100,000 b. 1,000,000c. 10000d. 10,000 e. 10,000,000
The mass of an average blueberry is 0.76 g and the mass of an automobile is 2200 kg . Find the number of automobiles whose total mass is the same as 1.0 mol blueberries. Express your answer using two significant figures.
Without doing any calculations, determine which of the samples contains the greatest amount of the element in moles. Which contains the greatest mass of the element? a. 55.0 g Crb. 45.0 g Tic. 60.0 g Zn
How many grams is a water molecule?a. 2x1023 gb. 3x1023 gc. 3x10-23 gd. 8x10-23 ge. 5x10-19 g
You must use Dimensional Analysis and answer the question.A gaseous sample of methane, CH4, has a density of 0.66 g/L. How many hydrogen atoms are in 2.41 L of the sample?
The molar mass of zinc is 65.39 g/mol. How many moles of zinc are there in a 75.0 g sample of zinc?
How many chlorine atoms are in 0.650 mol of Ca(ClO 4)2?
How many carbon atoms are present in a mole of 12C?
What is the mass of 5.45 x 10 -3 mol of glucose C6H12O6?A) 0.158 gB) 982 mgC) 3.03 x 10-5 gD) 9.82 x 102 g E) 164 mg
How many grams of P is contained in one mole of Mg 3(PO4)2?   
What is the mass (g) of silicon represented by  0.250 moles of elemental silicon? 
How many moles are there in 7.0 mL of N,N-dimethylaniline? Density of N,N-dimethylaniline is 0.956 g/mL and its molar mass is 121.19 g/mol. Show your work.
How many moles of manganese atoms are in 19.36 g of manganese metal?  
How many atoms of calcium are in 4.008g of calcium metal?     
How many oxygen atoms are there in 1.55 ng of Ca 3(PO4)2 ?A) 3.01 x 1012B) 1.20 x 1013C) 3.01 x 1018D) 1.21 x 1016E) 2.41 x 1013
The molar mass of HNO3 is 63.01g/mol,  perform each of the following conversions i) convert 13.9 g of HNO3 to moles and ii) convert 2.507 moles of HNO3 to grams
How many Na atoms are there in 1.50 mol Na?a.1.50   b. 9.03 X´1023  c. 3.00  d. 2.49 X´10-24   e. 345
How many moles of water, H2O, are present in 75.0g H 2O?a. 4.17 molesb. 4.41 molesc. 75.0 molesd. 1.35 x 103 molese. 7.50 moles
The density of methanol, CH3OH, is 0.792g/cm3 at 20°C.a. What volume of methanol contains Avogadro's number of molecules?b. How many molecules are in exactly 1g of methanol?c. How many hydrogen atoms?
Which statement below is true?a. The number of Ni atoms in 100 moles of Ni (s) is the same as the number of Ni atoms in 100 moles of nickel (II) chloride, NiCl2.b. One moles of NH 3 weighs more than one mole of H 2O.c. There are equal numbers of nitrogen atoms in one mole of NH 3 and one mole of N 2.d. The number of Cu atoms in 100 grams of Cu (s) is the same as the number of Cu atoms in 100 grams of copper (II) oxide, CuO.e. There are more hydrogen atoms in 2 moles of NH 3 than in 2 moles of CH 4.
Determine the molar mass of potassium hydrogen phthalate (KHP). The molecular formula is KHC8H4O4 .
If 200.0 g of zinc sulfide contains 134.2 g of zinc, what mass of zinc in g is contained in 3.3 kg of zinc sulfide?
A given sample of a xenon fluoride compound contains molecules of the type XeFn, where n is some whole number. Given that 9.03 x 1020 molecules of XeFn weighs 0.368 g, determine the value for n in the formula.
How many moles of sulfur are in 12.4 moles Al 2(SO4)3?a. 3b. 12.4c. 37.2d. 32
A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8 g/mol, and that its density is 0.97 g/L, how many molecules of air do you take in with each breath?A. 1.7 x 1025B. 1.8 x 1025C. 2.0 x 1022D. 2.2 x 1022E. 5.8 x 1023
How many grams of oxygen are in 12.4 moles Al 2(SO4)3?a. 2.38 x 103 g Ob. 9.30 g Oc. 12 g Od. 192 g O
There are currently 7.37 billion people in the world. If we distributed 1 mole of pennies to everyone evenly, how many dollars would each person get?a). 8.17 Trillion Dollarsb). 817 Billion Dollarsc). 81.7 Thousand Dollarsd). 817 Million Dollarse). 81.7 Trillion Dollars
Some bismuth tablets, a medication used to treat upset stomachs, contain 262 mg of bismuth subsalicylate, C7H5BiO4, per tablet. Assuming two tablets are digested, calculate the mass of bismuth consumed.
Find the number of ibuprofen molecules in a tablet containing 200.0 mg of ibuprofen (C13H18O2).
What is the amount, in moles, of each elemental sample?d. 0.211 g Li
A 0.755-g sample of hydrated copper(II) sulfate CuSO4 • xH2O was heated carefully until it had changed completely to anhydrous copper(II) sulfate (CuSO4) with a mass of 0.483 g. Determine the value of x. [This number is called the number of waters of hydration of copper(II) sulfate. It specifies the number of water molecules per formula unit of CuSO4 in the hydrated crystal.]
How many atoms are contained in one formula unit of aluminum dichromate, Al2(Cr2O7)3?a. 14b. 25c. 27d. 29e. none of these
Calculate the molar mass of ALUM, KAl(SO 4) 2 . 12H2O or potassium aluminum sulfate dodecahydrate. Be sure to include the twelve waters of hydration in the molar mass.
The molar mass of potassium phosphate (K 3PO4) isA) 173.17B) 251.37C) 212.27 
a. Calculate the formula weight of ethanol, C 2H5OH.b. Calculate the formula weight of Mg(NO 3)2.
How many moles of atoms are in 9.00 g of  13C?
A salt crystal has a mass of 0.15mg. How many NaCl formula units does it contain? Express your answer using 2 significant figures.
How many grams of CO 2 are in 2.1 mol of the compound?a. 21.0 gb. 44.0 gc. 66.0 gd. 92.4 g
What is the mass (in grams) of 9.83 x 1024 molecules of methanol (CH3OH)?
How many atoms are in 183 g of calcium?
Calculate the formula mass for each of the following halogen compounds to five or more significant figures:(a) NalO3  (antiseptic)(b)C14H9Cl6 (DDT)
The mineral galena is composed of lead(II) sulfide and has an average density of 7.46 g/cm3.(a) How many moles of lead(II) sulfide are in 6.35 ft3 of galena?(b) How many lead atoms are in 8.69 dm3 of galena?(Enter your answer in scientific notation.)
Calculate the number of O atoms in 0.00105 g of CaSO4•2H2O______ x 10___ O atoms (Enter your answer in scientific notation.)
Calculate the mass in kilograms of 32.7 mol of CuCl2 + H2O. 
Iron reacts slowly with oxygen and water to form a compound commonly called (Fe2O3 4H2O). For 35.7 kg of rust, calculate the following quantities.(a) The moles of compound: ___moles of rust(b) The moles of Fe2O3(c) The grams of iron:
Be sure to answer all parts.The atomic mass of Cl is 35.45 amu, and the atomic mass of Al is 26.98 amu. What are the masses in grams of 3.3356 mol of Cl atoms and of 7.9360 mol of Al atoms?
Calculate the number of atoms in each sample
Calculate the mass (in g) of a single maltose molecule (C12H22O11). Express your answer using four significant figures
Complete the following table.Part A Complete the second column of the table.Enter your answers numerically separated by a comma. Part B Complete the third column of the table.Enter your answers numerically separated by a comma.
A chemist requires 0.450 mol Na2CO3 for a reaction. How many grams does this correspond to?
Calculate the number of moles of oxygen atoms in 35.2 grams of oxygen.a. 2.20 molesb. 4.42 molesc. 1.13 molesd. 0.54 molese. 2.57 moles 
How many atoms are in 171 g of calcium?
What is the mass (in grams) of 9.88 x 1024 molecules of methanol (CH3OH)?
How many grams of hydrogen are in 92 g of CH4O?a. 5.8b. 4.0c. 120d. 12e. 63 
You may want to reference ( pages 107-110) section 3.8 while completing this problem. How many moles (of molecules or formula units) are in each sample?Part A60.91 g CF2Cl2 Express your answer to four significant figures and include the appropriate units.  Part B 24.9 kg Fe(NO3)2 Express your answer to three significant figures and include the appropriate units. 
An aspirin tablet contains 325.0 mg of aspirin, which has the molecular formula C9H8O4. Part 1How many moles of aspirin are in the tablet? Part 2How many molecules of aspirin are in the tablet? 
What would you multiply "moles of cobalt" by to get the units "grams of cobalt"? 
How many hydrogen ATOMS are there in 100.0 grams of H20? (a) 3.35 x 1024 hydrogen atoms (b) 6.69 x 1024 hydrogen atoms (c) 9.23 x 10-24 hydrogen atoms (d) 1.85 x 10-23 hydrogen atoms
You may want to reference (LD pages 57-61) Section 1.10 while completing this problem. What is the mass, in grams, of each of the following?Part A2.0 x 10-3 mol Sb Express your answer using two significant figures.  Part B 3.59 x 10-2 mol Ba Express your answer using three significant figures. 
Calculate the number of moles in 91.9 g SO3.
On another planet, the isotopes of titanium have the following natural abundances. What is the average atomic mass of titanium on that planet?
How many total atoms are in 0.830 g of P2O5? 
A mothball, composed of naphthalene (C10H8), has a mass of 1.30 g. How many naphthalene molecules does it contain?
How many GRAMS of sulfur are present in 3.88 grams of sulfur dioxide? How many GRAMS of sulfur dioxide can be produced from 3.44 grams of oxygen? 
Calculate the number of molecules in 5.00 moles H2S. Express your answer numerically in molecules.
What is the mass (in grams) of 9.57 x 1024 molecules of methanol (CH3OH)? 
What is the mass (in grams) of 9.50 x 10 24 molecules of methanol (CH3OH)? 
Ascorbic acid, or vitamin C (, molar mass = 176 g/mol), is a naturally occurring organic compound with antioxidant properties. A healthy adult's daily requirement of vitamin C is 70-90 mg. A sweet lime contains 2.88 times 10^-4 mol of ascorbic acid. To determine whether the ascorbic acid in a sweet lime meets the daily requirement, calculate the mass of ascorbic acid in 2.88 x 10^-4 mol of ascorbic acid. Express the mass in grams to three significant figures.
Calculate the number of particles in each of the following. 0.135 mol iron atoms, Fe. 0.252 mol nitrogen molecules, N2. 0.677 mol iron (III) nitride formula units.
How many moles of nitrogen, N, are in 69.0 g of nitrous oxide, N2O?
Composition of Seawater A 1-liter sample of seawater contains 19.4 g of CI-, 12.77 g of Na+, and 1.79 g of Mg2+.(a) How many moles of each ion are present?(b) If we evaporated the seawater, would there be enough CI- present to form the chloride salts of all the sodium and magnesium present?
Be sure to answer all parts.How many moles are contained in each number of grams of fructose (C 6H12O6. molar mass 180.2 g/mol), a carbohydrate that is about twice as sweet as table sugar? "Lite" food products use half as much fructose table sugar to achieve the same sweet taste, but with fewer calories. Enter your answer in scientific notation. a. 0.720 g b. 6.10 g 
How many moles of N are in 0.171 g of N 2O? 
What is the mass, in grams, of 2.5 moles of HCI? (a) 14.6 grams (b) 0.0685 grams (c) 0.011 grams (d) 91.3 grams
Be sure to answer all parts.Calculate the number of H- ions in 61.0 g of CaH 2.Enter your answer in scientific notation.
How many grams of phosphorus, P, would contain the same number of atoms as 58.693 g of nickel, Ni? 
How many moles of Br are there in a sample of Br that contains 1.73 x 10 24 atoms? ____ moles 
Calculate the mass, in grams of each of the following1.8x1023 lead atoms
A penny has a mass of 2.50 g and the Moon has a mass of 7.35 x 1022 kg. Use this information to answer the questions below. Be sure your answers have the correct number of significant digits. What is the mass of 1 mole of pennies? How many moles of pennies have a mass equal to the mass of the Moon?
A sugar crystal contains approximately 2.1 x 1017 sucrose (C12H22O11) molecules. What is its mass in mg? Express your answer using two significant figures.
How many MOLES of xenon trioxide are present in 3.83x1022 molecules of this compound?
How many ATOMS of carbon are present in 5.85 grams of carbon toe carbon e? _____ atoms of 
1. How many ATOMS of sulfur are present in 2.89 grams of sulfur dioxide? 2. How many GRAMS of oxygen are present in 4.42 x 1022 molecules of sulfur dioxide?
How many moles of MgSiO3 are in 223 g of the compound?
Enter your answer in the provided box.Calculate the mass in grams of 3.88 mol of LiMnO 4. 
How many moles of magnesium are in a 9.00 g sample of the metal? 
How many helium atoms are there in a helium blimp containing 540 kg of helium? Express the number of helium atoms numerically.
How many GRAMS of chromium(III) are present in 4.34 grams of chromium(III) carbonate? How many GRAMS of chromium(III) carbonate can be made from 2.52 grams of chromium(III)? 
Convert 2.01 g of CoCl2 to moles CoCl2. Molecular weight of CoCl2 is 129 g/mol. a. 0.016 mol b. 64.5 mol c. 65 mol d. 0.0155 mol
Be sure to answer all parts.What is the mass in grams of each quantity of lactic acid (C 3H4O3 molar mass 90.08 g/mol) the compound responsible for the aching feeling of tired muscles during vigorous exercise? a 7.50 molb. 0.540 mol
Calculate the number of moles in 8.56 x 1022 NO2 molecules.
Calculate the number of atoms in a 4.95 x 103 g sample of sulfur.
Calculate the number of moles of NBr3 in 52.5 g NBr3. Use a molar mass with at least as many significant figures as the data given. 
Tia has a sample of pure gold (Au). She weighed the sample and the result was 46.7 grams. Tia wants to determine the number of atoms in the sample. Calculate the number of atoms in 46.7 g of pure gold.  
How many total atoms are there in 51.1 g of ammonia (NH3)?
How many moles of MgS2O3 are in 243 g of the compound? 
Calculate the mass in grams of 11.6 mol of chromium(III) sulfate decahydrate. Enter your answer in scientific notation. 
How many MOLECULES of xenon trioxide are present in 2.63 moles of this compound .
What is the mass of exactly 1 mol of the following compounds? 
Be sure to answer all parts.Calculate the mass in grams of 7.25 x 10 18 molecules of diarsenic pentaoxide. Enter your answer in scientific notation.
Calculate the mass, in grams, of 1.75 mol of argon, Ar.Calculate the mass, in grams, of 0.727 mol of sulfur dioxide, SO2. 
If 8.95 moles of C5H12 reacts with excess O2, how many moles of CO2 will be produced in the following combustion reaction? 
What is the mass of 0.111 mole of MgCO3?
How many moles of aspirin, C9H8O4, are in a 500 mg tablet?
1. How many ATOMS of sulfur are present in 2.89 grams of sulfur dioxide? 2. How many GRAMS of oxygen are present in 4.42 x 1022 molecules of sulfur dioxide?
How many iron atoms are present in 0.552 mol of iron? a. 2.798 x 1024 b. 6.02 x 1023 c. 3.32 x 1023* d. 27.98
9.81 x 1019 CH4 molecules Express your answer using three significant figures.
How many GRAMS of carbon are present in 3.13 grams of carbon tetrabromide? How many GRAMS of carbon tetrabromide can be produced from 1.05 grams of bromine? 
A chemist requires 0.537 mol Na2CO3 for a reaction. How many grams does this correspond to?
How many moles of N are in 0.219 g of N2O?
28.5 mol of P4O10 contains how many moles of P?
How many grams of bromine are present in 2.68x1022 molecules of carbon tetrabromide
1. How many MOLECULES of boron trichloride are present in 1.95 moles of this compound? 2. How many MOLES of boron trichloride are present in 7.77 x 1022 molecules of compound? 
Calculate the mass of 0.520 moles of Cu(OH)2. Use a molar mass with at least as many significant figures as the data given. 
You are given a sample containing 0.90 moles of a substance. a) How many atoms are in the sample if the substance is lead? b) How many atoms are in the sample if the substance is titanium? c) How many molecules are present in the sample if the substance is propanol, C3H7OH? 
The mass of a single uranium atom is 4.70 x 10-22 grams. How many uranium atoms would there be in 224 milligrams of uranium? 
How many grams are contained in 1.90 mol of each compound? Do not convert these answers to scientific notation. a. HCI g b. Na2SO4 g
complete the formula for the number of atoms per unit volume N = _______ 
Calculate the amount, in moles, of each of the following. You may round atomic masses to one decimal place.21.1 g Na2S2O8 Express your answer with the appropriate units. 
How many moles of P are there in a sample of P that contaies 4.06 x 1024 atoms? 
Calculate the mass (in g) of 7.41 moles of H2O.
Be sure to answer all parts.How many grams are contained in 3.90 mol of each compound? Do not convert these answers to scientific notation. a. C2H2 g b. AI(OH)3 g
A chemist weighed out 4.4 g of mercury. Calculate the number of moles of mercury she weighed out. Be sure your answer has the correct number of significant digits. 
Calculate the mass, in grams, of each of the following. You may want to reference ( pages 57-61) Section 1.10 while completing this problem. Part A1.0 x 1023 gold atomsExpress your answer using three significant figures.Part B 2.86 x 1022 helium atoms Express your answer using three significant figures. 
How many atoms are in 137 g of calcium? 
How many moles of MgSiO3 are in 185 g of the compound?
You are given a sample containing 0.10 moles of a substance. a) How many atoms are in the sample if the substance is copper? b) How many atoms are in the sample if the substance is titanium? c) How many molecules are present in the sample if the substance is propanol, C3H7OH?
How many bromines atoms are present in 37.5 g of CH2Br2? Express the number of atoms to three significant figures.
How many moles are in each of the following samples? 1.157 kg of U Express the amount in moles to four significant digits.
A typical adult body contains 6 liters of blood. The hemoglobin content of blood is about 15.5 g/100 mL of blood. The approximate molecular weight of hemoglobin is 64, 500 g/mol. How many moles of hemoglobin are present in a typical adult?
What is the mass (in grams) of 9.25 x 1024 molecules of methanol (CH3OH)?
How many moles are contained in each number of grams of fructose (C 6H12O6 molar mass 180.2 g/mol), a carbohydrate that is about twice as sweet as table sugar? "Lite" food products use half as much fructose as table sugar to achieve the same sweet taste, but with fewer calories. Enter your answer in scientific notation. a. 19.0 g b. 0.0820 g 
The fuel used in many disposable lighters is liquid butane, C4H10. Butane has a molecular weight of 58.1 grams in one mole. How many carbon atoms are in 1.50 g of butane? Express the number of atoms to three significant figures.
Calculate the mass, in grams of each of the following1.0x1023 gold atoms
How many S atoms are there in 3.52 moles of S? ____ atoms 
How many moles of aluminum do 6.5 x 1024 aluminum atoms represent? Express your answer using two significant figures. 
a. How much aluminum is produced from 4.90 x 10 3 kg of AI2O3? b. The oxygen produced in part (a) is allowed to react with carbon to produce carbon monoxide. Write a balanced equation describing the reaction of alumina with carbon. [You need not include the states of matter in the balanced equation.] 3C + AI2O3 → 3CO + 2AI How much CO is produced from the alumina in part (a)? 
How many moles of atoms are in each elemental sample? Part A 1.86 g Zn Part B26.6 g Ar Part C 89.0 g Ta
How many molecules are present in each of the following samples? a) 3.5 mol of SO2 b) 0.383 mol of CO c) a sample of NH3 containing Avogadro's number of molecules 
Which sample contains the greatest number of atoms? (a) 34 gP (b) 70 gSe (c)8 gGa 190 gAu
What is the mass of 3.5 x 1022 molecules of CO2? a. 5.9 x 10-2 g b. 2.6 g* c. 1.8 x 1024 g d. 1.5 x 10-3 g
How many S atoms are present in 7.00 mg of allicin? Express your answer using three significant figures. 
63.1 mmol SeO2 Express your answer with the appropriate units. 
Calculate the number of moles in 10.0 grams of BaF2. a. 9.77 mol b. 0.115 mol c. 17.4 mol d. 0.0570 mol*
What is the average molecular weight (in g/gmol) of the following mixture: 10.0 mole% C2H5 OH. 75.0 mole% C4H8O2, and 15.0 mole% CH3COOH. Select one: 
Calculate the mass, in grams, of each of the following. You may want to reference ( pages 57-61) Section 1.10 while completing this problem. Part C1.8 x 1023 lead atomsExpress your answer using two significant figures.Part D7.7 x 1021 uranium atomsExpress your answer using two significant figures.
A chemist weighed out 101 g of silver. Calculate the number of moles of silver she weighed out. Be sure your answer has the correct number of significant digits.
If you have 213.12g of Ca 3(PO4)2, how many moles do you have? How many grams of NaCl are there in 0.2611 mol? 
Calculate the following in 7.54 g Li3PO4. 
Calculate the mass of 2.25 x  10 2 tungsten atoms. Express the mass in grams to three significant figures. 
A sample of hydrogen sulfide, H2S, has a mass of 19.00 g. Calculate the number of hydrogen sulfide molecules in the sample. 
How many grams of iron (III) oxide are there in a 0.125-mole sample of iron (III) oxide?a. 6 23 gramsb. 20.0 gramsc. 17.5 gramsd. 0.346 gramse. 32.3 gramsf. 1.95 grams 
What is the molar mass of cholesterol if 0.00105 mol weighs 0.406 g? Express your answer using three significant figures.
How many atoms are in 159g of calcium? 
A sample of C3H8 has 6.40 x 104 H atoms.How many carbon atoms does the sample contain?
How many oxygen atoms are present in each of the following formulas? H2SO4 C5H10O Cu(NO3)2Al(OH)3
How many calcium ions are there in 4.14 mol Ca3N2? Express your answer to three significant figures. 
The mass of a single niobium atom is 1.54 x 10-22 grams. How many niobium atoms would there be in 83.6 milligrams of niobium?
Calculate the following in 6.00 g Li3PO4 a) Li+ ions b) grams O
What is the mass (in grams) of 9.69 x 1024 molecules of methanol (CH3OH)?
Complete the table.Complete the second column of the table. Enter your answers numerically separated by a comma. Complete the third column of the table. Enter your answers numerically separated by a comma.
Calculate the mass of 1.5 mol of C6H12O6.a. 6.022 x 1023 g C6H12O6b. 270 g C6H12O6c. 180 g C6H12O6d. 1.5 g C6H12O6  
Hydrazine, N2H4, may react with oxygen to form nitrogen gas and water.N2H4 (aq) + O2 (g) → N2 (g) + 2H2O (l)If 2.35 g of N2H4 reacts and produces 0.450 L of N2, at 285 K and 1.00 atm, what is the percent yield of the reaction.
How many grams of Pb are contained in a mixture of 0.165 kg each of PbCl (OH) and Pb2Cl2CO3? 
Part AHow many O atoms of mass 16.00 amu are in 14.8 g of oxygen? Express your answer using four significant figures.
How many moles are in each of the following samples? 29.408 g of Na Express the amount in moles to five significant digits. 
Be sure to answer all parts.How many moles and numbers of ions of each type are present in the following aqueous solution? 377 mL of 0.285 g aluminum sulfate/L: 
Be sure to answer all parts.Calculate the number of O atoms in 0.207 g of CaSO4-2H2O. _________ (Enter your answer in scientific notation.)
Calculate the molar masses of the following atmospheric molecules: a. CO b. N2O c. CH4 d. NO2
1. How many MOLECULES of xenon trioxide are present in 2.63 moles of this compound? 2. How many MOLES of xenon trioxide are present in 3.83 x 1022 molecules of this compound? 
How many grams of F are in 455 g of CaF2? 
1. What is the mass of 5.65 x 1023 atoms of beryllium? 2. How many beryllium atoms are there in 25.3 grams of beryllium?
1. How many ATOMS of phosphorus are present in 1.91 grams of phosphorus pentachloride, PCI5? 2. How many GRAMS of chlorine are present in 3.28 x 1021 molecules of phosphorus pentachloride? 
How many Co atoms are there in a 51.2 gram sample of Co? 
The uranium used for nuclear fuel exists in nature in several minerals. Calculate how many moles of uranium are in 5 moles of each of the following. (a) carnotite, K2(UO2)2(VO4)2•3H2O mol (b) uranophane, CaU2Si2O11•7H2O mol (c) autunite, Ca(UO2)2(PO4)2•1OH2O mol How many moles of carbon are there in 580.0 grams of carbon?
The molar mass of carbon is 12.01 g/mole. What is the mass of a 1.0 x 109 carbon atoms? (Avogadro's # = 6.022 x 1023 atoms) a. 1.4 x 10-16 g b. 2.0 x 10-14 g c. 1.2 x 10-8 g d. 8.3 x 107 g
1. How many ATOMS of nitrogen are present in 4.80 moles of nitrogen trifluoride?2. How many MOLES of fluorine are present in 9.96 x 1022 molecules of nitrogen trifluoride?
 A chemist requires 0.786 mol Na2CO3 for a reaction. How many grams does this correspond to? 
Enter your answer in the provided box.How many moles of strontium (Sr) atoms are in 62.2 g of Sr?
A small kidney stone might contain 0.47 g of uric acid (C 5H4N4O3). Part AHow many micromoles of uric acid are contained in this stone? Express your answer using two significant figures.
What is a correct method for calculating the number of atoms in 3.5 x 10-3 mole Cr?
The concentrations of Ca and Na in a sample of riverwater are 13.4 mg/kg and 5.2 mg/kg, respectively. Express the concentration in molality.
How many MOLES of phosphorus triodide are present in 6.20x1022 molecules of this compound?
How many moles of C24H29O6 molecules are in 109 mg of this compound? What is the mass of 0.160 mol of this compound? How many carbon atoms are in 2.87 pg of this compound?What is the mass of 4.15 x 1012 molecules of this compound?
Methane (CH4) is a greenhouse gas. How many hydrogen ATOMS are in 1.4 moles of methane? a. 8.4 x 1023 atoms H b. 2.1 x 1023 atoms H c. 3.4 x 1024 atoms H d. 6.2 x 1024 atoms H
You may want to reference ( pages107. 110) section 3.8 while completing this problem. How many moles (of molecules or formula units) are in each sample?Part C0.2603 g C8H18Express your answer to four significant figures and include the appropriate units.  Part D 196 kg CaO Express your answer to three significant figures and include the appropriate units. 
A chemist determines by measurements that 0.0650 moles of iodine solid participate in a chemical reaction. Calculate the mass of iodine solid that participates. Be sure your answer has the correct number of significant digits.
How many molecules of CO are present? 
The 69.5-g sample of the compound X3O4 contains 19.2 g of oxygen atoms. What is the molar mass of element X?
How many Be atoms are there in a 39.1 gram sample of Be? ______ atoms 
Calculate the amount, in moles, of each of the following. You may round atomic masses to one decimal place. 15.6 g SF6 Express your answer with the appropriate units.
What is the mass of 0.500 mol of carbon tetrachloride CCl 4?a. 76.9 gb. 308 gc. 3.25 x 10-3gd. 154 g 
For we given elements, convert 1.00 gram of that element to moles. How many moles of magnesium are in 1.00 gram? How many moles of zinc are in 1.00 gram? How many moles of xenon are in 1.00 gram?
1. How many MOLECULES of nitrogen trifluoride are present in 4.47 moles of this compound ? 2. How many MOLES of nitrogen trifluoride are present in 1.03 x 1023 moles of this compound ? 
A chemist requires 0.900 mol Na2CO3 for a reaction. How many grams does this correspond to? 
Convert 1.31 x 1024 atoms of carbon to moles of carbon. 
How many MOLECULES of phosphorus triiodide are present in 2.61 moles of this compound?
How many moles of carbon are there in 60.053 grams of carbon. Roundoff to the closet whole number
How many moles of zinc, Zn, are in 1.39 x 1024 Zn atoms?
Calculate the molar mass of each compound given below. Keep at least one decimal place in atomic masses from the periodic table. a) Nal b) Na2S
1.46 x 10-3 mol H2O Express your answer with the appropriate units. 
You may want to reference (LD pages 57-61) Section 1.10 while completing this problem. What is the mass, in grams, of each of the following?Part C43.9 mol XeExpress your answer using three significant figures.Part D1.2 mol WExpress your answer using three significant figures.
How many moles of ammonia, NH3, are there in 250 grams of ammonia? Do NOT include units in your answer.
A sugar contains approximately 2.4 x 1017 (C12H22O11) molecules. What is its mean in milligrams? Express your answer using two significant figures. 
Brontis is working in his lab. To continue his experiment, he needs to calculate the total number of ions in 3.13 mol of MgCl2. Calculate the total number of ions in 3.13 mol of MgCl 2. 
Be sure to answer all parts.How many moles are contained in each number of grams of table sugar (C 12H22O11 molar mass 342.3 g/mol)? Enter your answer in scientific notation. a. 95.0 g b. 0.0440 g 
Which of the following could you reasonably measure on a typical laboratory scale or balance? a. 1 molecule of NO2 b. 1 mole of marbles c. 1 mole of Na2SO4 d. 1 atom of gold
Calculate the molar mass of each compound given below. Keep at least one decimal place in atomic masses from the periodic table.a. LiCl ________ g/molb. K3N__________ g/mol 
How many grams of carbon, C, would contain the same number of atoms as 32.066 g of sulfur, S? 
How many helium atoms are contained in 3.75 moles of helium?a. 1.23 x 1024 helium atomsb. 9.03 x 1024 helium atomsc. 1.61 x 1023 helium atomsd. 6.50 x 1025 helium atomse. 2.26 x 1024 helium atoms 
Which of the following contains the Fewest atoms? You shouldn't do a calculation here.10.0 g Kr10.0 g Na10.0 g Ca10.0 g Ae10.0 g Li
How many atoms of titanium are there in 0.500 mole of each of the following?
Part AWhat is the mass, in grams, of 1.50 mol of iron (III) sulfate? Part BHow many moles of ammonium ions are in 6.935 g of ammonium carbonate? Part CWhat is the mass, in grams, of 1.40 x 1021 molecules of aspirin, C9H8O4? Express your answer using three significant figures.
What is the percentage of iron in iron(III)oxide?a. 30%b. 70% c. 60%d. 40% 
A solution of ammonia and water contains 4.00 x 1025 water molecules and 8.60 x 1024 ammonia molecules How many total hydrogen atoms are in this solution? Enter your answer numerically.
1 mole of which of the following will have the largest mass?a. magnesiumb. rubidiumc. neond. mercurye. 1 mole of any element will contain the same mass 
1. How many moles of Ni are there in a sample that contains 15.8 grams of nickel? 2. How many grams of nickel are there in a sample that contains 1.22 mol of Ni?