Chemistry Chemistry Practice Problems Solutions Library

Mole Concept Solutions Library

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928 solutions

Mole Concept

Q. 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 ...

Solved • Jul 21, 2016

Mole Concept

Q. 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 ...

Solved • Jul 21, 2016

Mole Concept

Q. 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 ...

Solved • Jul 21, 2016

Mole Concept

Q. 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 ...

Solved • Jul 21, 2016

Mole Concept

Q. 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 u...

Solved • Jul 21, 2016

Mole Concept

Q. 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 mo...

Solved • Jul 21, 2016

Mole Concept

Q. 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 ...

Solved • Jul 21, 2016

Mole Concept

Q. 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?

Solved • Jul 21, 2016

Mole Concept

Q. Calculate the molar mass of the following substances.c. Na 2HPO4

Solved • Jul 21, 2016

Mole Concept

Q. Calculate the molar mass of the following substances.b. Ca 3(PO4)2

Solved • Jul 21, 2016

Mole Concept

Q. Calculate the molar mass of the following substances.

Solved • Jul 21, 2016

Mole Concept

Q. The Freons are a class of compounds containing carbon, chlorine, and fluorine. While they have many valuable uses, they have been shown to be respo...

Solved • Jul 21, 2016

Mole Concept

Q. 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?

Solved • Jul 21, 2016

Mole Concept

Q. 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)?

Solved • Jul 21, 2016

Mole Concept

Q. What number of Fe atoms and what amount (moles) of Fe atoms are in 500.0 g of iron?

Solved • Jul 21, 2016

Mole Concept

Q. Calculate the mass of 500. atoms of iron (Fe).

Solved • Jul 21, 2016

Mole Concept

Q. A sugar crystal contains approximately 1.8 x 1017 sucrose (C12H22O11) molecules. What is its mass in mg?

Solved • May 30, 2016

Mole Concept

Q. Calculate the mass (in g) of each sample.c. 1 water molecule

Solved • May 30, 2016

Mole Concept

Q. Calculate the mass (in g) of each sample.b. 9.85 x 1019 CCl2F2 molecules

Solved • May 30, 2016

Mole Concept

Q. Calculate the mass (in g) of each sample.a. 4.5 x 1025 O3 molecules.

Solved • May 30, 2016

Mole Concept

Q. Phosphorus is obtained primarily from ores containing calcium phosphate. If a particular ore contains 57.8% calcium phosphate, what minimum mass of...

Solved • May 30, 2016

Mole Concept

Q. 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...

Solved • May 30, 2016

Mole Concept

Q. How many molecules are in each sample?d. 19.3 g C8H10

Solved • May 30, 2016

Mole Concept

Q. How many molecules are in each sample?c. 22.1 g O2

Solved • May 30, 2016

Mole Concept

Q. How many molecules are in each sample?b. 389 g CBr4

Solved • May 30, 2016

Mole Concept

Q. How many molecules are in each sample?a. 6.5 g H2O

Solved • May 30, 2016

Mole Concept

Q. How many moles (of molecules or formula units) are in each sample?d. 195 kg CaO

Solved • May 30, 2016

Mole Concept

Q. How many moles (of molecules or formula units) are in each sample?c. 0.1187 g C8H18

Solved • May 30, 2016

Mole Concept

Q. How many moles (of molecules or formula units) are in each sample?b 23.6 kg Fe(NO3)2

Solved • May 30, 2016

Mole Concept

Q. How many moles (of molecules or formula units) are in each sample?a. 55.98 g CF2Cl2

Solved • May 30, 2016

Mole Concept

Q. Calculate the formula mass for each compound. d. Ca(NO3)2

Solved • May 30, 2016

Mole Concept

Q. Calculate the formula mass for each compound. c. CBr4

Solved • May 30, 2016

Mole Concept

Q. Calculate the formula mass for each compound. b. HNO2

Solved • May 30, 2016

Mole Concept

Q. Calculate the formula mass for each compound. a. MgBr2

Solved • May 30, 2016

Mole Concept

Q. 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 ki...

Solved • May 30, 2016

Mole Concept

Q. 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. 

Solved • May 30, 2016

Mole Concept

Q. 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.

Solved • May 27, 2016

Mole Concept

Q. Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).d. CF3Cl

Solved • May 26, 2016

Mole Concept

Q. Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).c. C2F3Cl3 

Solved • May 26, 2016

Mole Concept

Q. Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).b. CFCl3

Solved • May 26, 2016

Mole Concept

Q. Calculate the mass (in kilograms) of chlorine in 25 kg of each chlorofluorocarbon (CFC).a. CF2Cl2

Solved • May 26, 2016

Mole Concept

Q. 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

Solved • May 26, 2016

Mole Concept

Q. A salt crystal has a mass of 0.12 mg. How many NaCl formula units does it contain? 

Solved • May 26, 2016

Mole Concept

Q. If 2.50 grams of an unknown compound contains 6.25 x 10 19 molecules, what is its molecular mass?   

Solved • May 26, 2016

Mole Concept

Q. 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

Solved • May 26, 2016

Mole Concept

Q. 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

Solved • May 26, 2016

Mole Concept

Q. 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

Solved • May 26, 2016

Mole Concept

Q. Without doing any calculations, determine which of the samples contains the greatest amount of the element in moles. Which contains the greatest ma...

Solved • May 23, 2016

Mole Concept

Q. 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 ...

Solved • May 23, 2016

Mole Concept

Q. What is the amount, in moles, of each elemental sample? c. 26.1 g Ta

Solved • May 23, 2016

Mole Concept

Q. What is the amount, in moles, of each elemental sample? b. 3.55 g Zn

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

Q. How many sulfur atoms are there in 3.8 mol of sulfur? 

Solved • May 23, 2016

Mole Concept

Q. 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? 

Solved • May 23, 2016

Mole Concept

Q. 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 ...

Solved • May 23, 2016

Mole Concept

Q. 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 coppe...

Solved • May 23, 2016

Mole Concept

Q.  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. 

Solved • May 23, 2016

Mole Concept

Q. 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 sa...

Solved • May 23, 2016

Mole Concept

Q. Using scanning tunneling microscopy, scientists at IBM wrote the initials of their company with 35 individual xenon atoms (as shown below). Calcula...

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

Q. 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 lithi...

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

Q. What is the mass, in grams, of each elemental sample?b. 0.0355 mol Ba

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

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

Solved • May 23, 2016

Mole Concept

Q. 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 1...

Solved • May 18, 2016

Mole Concept

Q. 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. ...

Solved • May 16, 2016

Mole Concept

Q. 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 cont...

Solved • May 13, 2016

Mole Concept

Q. 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 m...

Solved • May 12, 2016

Mole Concept

Q. 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 ...

Solved • May 6, 2016

Mole Concept

Q. 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

Solved • May 6, 2016

Mole Concept

Q. 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

Solved • May 6, 2016

Mole Concept

Q. 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

Solved • May 6, 2016

Mole Concept

Q. 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) Ag2O b) Cu2O c)...

Solved • Apr 26, 2016

Mole Concept

Q. 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

Solved • Apr 26, 2016

Mole Concept

Q. 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•mo...

Solved • Apr 26, 2016

Mole Concept

Q. 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 magne...

Solved • Apr 26, 2016

Mole Concept

Q. 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

Solved • Apr 26, 2016

Mole Concept

Q. 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 m...

Solved • Apr 26, 2016

Mole Concept

Q. 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

Solved • Apr 25, 2016

Mole Concept

Q. How many grams of P is contained in one mole of Mg 3(PO4)2?   

Solved • Apr 22, 2016

Mole Concept

Q. If the mass of 2.51 x 10 -3 moles of compound A is 0.452 g, then what is the molar mass?

Solved • Apr 21, 2016

Mole Concept

Q. 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  

Solved • Apr 20, 2016

Mole Concept

Q. 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 × 1...

Solved • Apr 8, 2016

Mole Concept

Q. 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 ...

Solved • Apr 8, 2016

Mole Concept

Q. 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

Solved • Apr 8, 2016

Mole Concept

Q. 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

Solved • Apr 8, 2016

Mole Concept

Q. 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 mole...

Solved • Apr 8, 2016

Mole Concept

Q. 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

Solved • Apr 8, 2016

Mole Concept

Q. 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 a...

Solved • Apr 7, 2016

Mole Concept

Q. 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 atom...

Solved • Apr 7, 2016

Mole Concept

Q. 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? ...

Solved • Mar 19, 2016

Mole Concept

Q. How many moles are in 26.7 grams of calcium nitrate?

Solved • Mar 11, 2016

Mole Concept

Q. 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  

Solved • Feb 25, 2016

Mole Concept

Q. 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 chlori...

Solved • Feb 23, 2016

Mole Concept

Q. 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

Solved • Feb 12, 2016