Practice: If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?

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Mole Concept | 38 mins | 0 completed | Learn Summary |

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Thomson's Cathode Ray Tube Experiment |

The Chadwick Neutron Experiment |

Mass Spectrometry |

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Periodic table Charges (IGNORE) |

Calculating Molar Mass (IGNORE) |

Calculating Grams to Moles (IGNORE) |

The **Mole Concept** involves the interconversions between different unit amounts of a substance.

Example #1: Which of the following compounds would not be associated with the term “formula unit”?

Example #2: How many moles of chlorine gas are there in 8.33 x 10^{37} molecules?

Example #3: How many grams of chlorine gas are there in 2.34 moles?

Example #4: How many grams of Cl_{2 }contain 9.25 x 10^{24} molecules of Cl_{2}?

Practice: If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?

Practice: Calculate the number of oxygen atoms found in 783.9 g NiCl_{2} • 6 H_{2}O.

Practice: If the density of water is 1.00 g/mL at 25°C, calculate the number of water molecules found in 1.50 x 10^{3} µL of water.

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/cm^{3}. (V = π • r^{2} • h)

Practice: The density of the sun is 1.41 g/cm^{3} and its volume is 1.41 x 10^{27} m^{3}. How many hydrogen molecules are in the sun if we assume all the mass is hydrogen gas?

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Concept #1: Mole Concept

Example #1: Mole Concept Example 1

Concept #2: Mole Concept

Example #2: Mole Concept Example 2

Concept #3: Mole Concept

Example #3: Mole Concept Example 3

Example #4: Mole Concept Example 4

Practice #1: Mole Concept Practice 1

Practice #2: Mole Concept Practice 2

Practice #3: Mole Concept Practice 3

Practice #4: Mole Concept Practice 4

Practice #5: Mole Concept Practice 5

How many Cl atoms are there in 27.3 grams of magnesium chloride?

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.

How many Cl atoms are there in 27.3 grams of magnesium chloride?

How many Cl– ions are there in 15.6 g of MgCl 2?

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

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 14-g sample of which isotope will have the largest number of atoms?
a. 13C
b. 14C
c. 13N
d. 14N
e. They would all have the same number of atoms.

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

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

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

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

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

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

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 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 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

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

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.

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 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

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

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

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+

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 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

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

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

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

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

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 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

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

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 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

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

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?

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

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

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

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 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

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

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

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

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

How many xenon atoms are contained in 2.36 moles of xenon?

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

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

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

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

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

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

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

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

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

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

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.

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 moles are in 26.7 grams of calcium nitrate?

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

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 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 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

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

When 1.187 of a metallic oxide is reduced with excess hydrogen, 1.054 g of the metal is produced. What is the metallic oxide?a) Cu2Ob) K2Oc) Ag2Od)TI2O

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.

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

What is the amount, in moles, of each elemental sample?d. 0.211 g Li

What is the mass, in grams, of each elemental sample?a. 2.3 x 10 –3 mol Sb

What is the mass, in grams, of each elemental sample?c. 43.9 mol Xe

What is the mass, in grams, of each elemental sample?d. 1.3 mol W

How many silver atoms are there in 3.78 g of silver?

Calculate the mass, in kg, of each sample.a. 7.55 x 1026 cadmium atomsb. 8.15 x 1027 nickel atomsc. 1.22 x 1027 manganese atomsd. 5.48 x 1029 lithium atoms

How many helium atoms are there in a helium blimp containing 536 kg of helium?

Calculate the average mass, in grams, of one platinum atom.

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.

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.

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.]

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 sulfur atoms are there in 3.8 mol of sulfur?

How many moles of aluminum do 5.8 X 1024 aluminum atoms represent?

What is the amount, in moles, of each elemental sample?a. 11.8 g Ar