Deck 4: The Mole and Stoichiometry

Question 1

An atom of copper has a mass about four times greater than that of an atom of oxygen. What choice makes the correct comparison of the relative numbers of copper and oxygen atoms in 1,000 g of each element?

A)The number of copper and oxygen atoms is the name.
B)There are one thousand times as many copper atoms as oxygen atoms.
C)There are one thousand times as many oxygen atoms as copper atoms.
D)There are four times as many oxygen atoms as copper atoms.
E)There are four times as many copper atoms as oxygen atoms.

Answer 1

There are four times as many oxygen atoms as copper atoms.

Question 2

An atom of sulfur is about four times smaller in mass than an atom of iodine. How many grams of neon will contain the same number of atoms as 1,000 g of iodine?

A)4 g S
B)250 g S
C)400 g S
D)1,000 g S
E)4,000 g S

Answer 2

250 g S

Question 3

Which of these quantities does not represent 1.00 mol of the indicated substance?

A)6.02 × 10²³ C atoms
B)26.0 g Fe
C)12.01 g C
D)65.4 g Zn
E)6.02 × 10²³ Fe atoms

Answer 3

26.0 g Fe

Question 4

The atomic mass of C is 12.011 u. How many moles of C are there in a 3.50 g sample of carbon?

A)0.291 moles
B)0.374 moles
C)1.00 moles
D)3.43 moles
E)3.50 moles

Question 5

The atomic mass of Mg is 24.305 u. How many moles of Mg are there in a 3.50 g sample of magnesium?

A)0.0182 moles
B)0.144 moles
C)0.218 moles
D)0.226 moles
E)1.31 × 10²³ moles

Question 6

The atomic mass of aluminum is 26.982 u. How many moles of Al are there in a 4.56 g sample of aluminum?

A)0.169 moles
B)0.220 moles
C)1.33 moles
D)4.55 moles
E)5.93 moles

Question 7

The atomic mass of chromium is 51.996 u. How many moles of Cr are there in a 5.44 g sample of chromium?

A)0.0875 moles
B)0.0907 moles
C)0.105 moles
D)0.220 moles
E)2.33 moles

Question 8

The atomic mass of cobalt is 58.933 u. How many moles of Co are there in a 7.60 g sample of cobalt?

A)0.106 moles
B)0.114 moles
C)0.123 moles
D)0.129 moles
E)7.79 × 10²² moles

Question 9

The atomic mass of helium is 4.0026 u. What is the mass of a helium sample that contains 0.427 moles of He gas?

A)0.427 g
B)0.107 g
C)1.71 g
D)2.57 g
E)9.37 g

Question 10

The atomic mass of cobalt is 58.993 u. What is the mass of a cobalt sample that contains 0.763 moles of cobalt?

A)39.7 g
B)40.3 g
C)43.4 g
D)45.0 g
E)45.7 g

Question 11

The atomic mass of boron is 10.811 u. What is the mass of a boron sample that contains 0.585 moles of boron?

A)0.00541 g
B)1.80 g
C)3.52 g
D)6.32 g
E)18.5 g

Question 12

The atomic mass of phosphorus is 30.974 u. What is the mass of a phosphorus sample that contains 0.585 moles of phosphorus?

A)17.3 g
B)18.1 g
C)22.3 g
D)26.5 g
E)34.2 g

Question 13

The molar mass of Co(NH₃)₆(ClO₄)₃ is

A)318.53 u.
B)389.43 u.
C)402.57 u.
D)459.47 u.
E)754.13 u.

Question 14

The molar mass of C₁₄H₂₈(COOH)₂ is

A)242.40 u.
B)254.41 u.
C)270.41 u.
D)273.39 u.
E)286.41 u.

Question 15

The molar mass of Ni(H₂O)₆Cl₂ is

A)157.69 u.
B)193.00 u.
C)227.61 u.
D)237.69 u.
E)296.83 u.

Question 16

The molar mass of (NH₄)₃PO₄ is

A)116.03 u.
B)121.07 u.
C)149.09 u.
D)155.42 u.
E)242.01 u.

Question 17

The molar mass of (NH₄)₂SO₄ is

A)84.12 u.
B)116.12 u.
C)118.13 u.
D)132.14 u.
E)221.53 u.

Question 18

A gas sample contains 16.0 g of CH₄, 16.0 g of O₂, 16.0 g of SO₂, and 33.0 g of CO₂. What is the total number of moles of gas in the sample?

A)2.25 moles
B)2.50 moles
C)2.75 moles
D)3.00 moles
E)4.00 moles

Question 19

The mass of 5.20 moles of glucose, C₆H₁₂O₆ is

A)1.56 × 10²¹ g.
B)31.2 g.
C)34.7 g.
D)937 g.
E)6.43 × 10²⁰ g.

Question 20

If the atomic mass of gold is 196.9665 u, how many grams of gold are in 0.150 mol Au?

A)7.62 × 10^-4 g
B)29.5 g
C)29.54498 g
D)7.61551 × 10^-4 g
E)0.903 g

Question 21

How many atoms of ¹²C are in a 3.50 g sample of this particular isotope?

A)1.52 × 10²³
B)1.75 × 10²³
C)2.07 × 10²⁴
D)2.11 × 10²⁴
E)8.01 × 10²³

Question 22

The atomic mass of aluminum is 26.982 u. How many aluminum atoms are in a 4.55 g sample of aluminum?

A)1.02 × 10²³
B)1.32 × 10²³
C)2.74 × 10²⁴
D)3.57 × 10²⁴
E)8.01 × 10²³

Question 23

The atomic mass of neon is 20.1797 u. What is the mass, in grams, of a neon sample which contains 1.00 × 10²⁰ neon atoms?

A)1.66 × 10^-4 g
B)2.02 × 10^-19 g
C)298 g
D)3.35 × 10^-3 g
E)8.33 × 10^-6 g

Question 24

The atomic mass of magnesium is 24.3050 u. What is the mass, in grams, of a magnesium sample which contains 3.22 × 10²² magnesium atoms?

A)1.30 g
B)12.2 g
C)1.99 g
D)5.88 g
E)7.50 × 10^-4 g

Question 25

How many molecules of carbon dioxide are in 154.0 grams of carbon dioxide? Hint: Think about your pathway to solving. Can you convert directly from mass to molecules or is there an intermediate unit you should use?

A)3.499
B)2.107 × 10²⁴
C)4.214 × 10²⁴
D)9.274 × 10²⁵
E)4.081 × 10²⁷

Question 26

How many formula units of sodium chloride are in 146 grams of sodium chloride? Hint: Think about your pathway to solving. Can you convert directly from mass to formula units or is there an intermediate unit you should use?

A)3.88 × 10^-22
B)2.29 × 10²⁴
C)1.50 × 10²⁴
D)7.27 × 10²⁵
E)4.08 × 10²³

Question 27

How many moles of carbon atoms are in 0.145 moles of the compound, C₃H₈?

A)2.90 moles
B)0.435 moles
C)0.145 moles
D)6.02 × 10²³ moles
E)29.9

Question 28

How many moles of oxygen atoms are in 1.08 moles of Ca(NO₃)₂?

A)7.55 moles
B)1.43 moles
C)6.48 moles
D)33.8 moles
E)1.16 × 10²³ moles

Question 29

A sample of Ca₃(PO₄)₂ contains 3.51 moles of calcium ions. How many moles of Ca₃(PO₄)₂ are in that sample?

A)3.55 moles
B)0.491 moles
C)10.5 moles
D)1.17 moles
E)3.51 × 10²¹ moles

Question 30

How many moles of carbon atoms are combined with 11.2 moles of hydrogen atoms in a sample of the compound, C₃H₈?

A)3.00
B)5.60
C)4.20
D)6.02 × 10²³
E)29.9

Question 31

A sample of C₁₂H₂₂O₁₁ contains 0.4662 moles of carbon atoms. How many moles of hydrogen atoms are in the sample?

A)0.2543 moles
B)0.4662 moles
C)10.26 moles
D)0.8547 moles
E)0.9324 moles

Question 32

A sample of HOOCC₆H₄OH contains 0.6540 moles of hydrogen atoms. How many moles of carbon atoms are in the sample?

A)0.6543 moles
B)6.090 moles
C)7.015 moles
D)1.290 moles
E)0.7630 moles

Question 33

A sample of Ni(CO)₄, a toxic transition-metal complex, has 5.23 × 10²⁴ atoms of carbon. How many atoms of Ni does it contain?

A)6.02 × 10²³ atoms
B)1.50 × 10²³ atoms
C)4.67 × 10²² atoms
D)20.9 × 10²³ atoms
E)1.31 × 10²⁴ atoms

Question 34

How many sodium atoms are in 6.0 g of Na₃N?

A)3.6 × 10²⁴ atoms
B)4.6 × 10²² atoms
C)1.3 × 10²³ atoms
D)0.217 atoms
E)0.072 atoms

Question 35

A sample of K₃Fe(CN)₆ contains 1.084 × 10²⁴ carbon atoms. How many potassium atoms are in the sample?

A)1.084 × 10²⁴ atoms
B)3.252 × 10²⁴ atoms
C)2.168 × 10²⁴ atoms
D)3.613 × 10²³ atoms
E)5.420 × 10²³ atoms

Question 36

A sample of phosphorus trifluoride, PF₃, contains 1.400 moles of the substance. How many atoms are in the sample?

A)4
B)5.6
C)8.431 × 10²³
D)2.409 × 10²⁴
E)3.372 × 10²⁴

Question 37

A sample of arabinose, C₅H₁₀O₅, contains 0.6000 moles of the substance. How many carbon atoms are in the sample?

A)3
B)5
C)3.613 × 10²³
D)1.807 × 10²⁴
E)3.011 × 10²⁴

Question 38

Which contains the greatest number of carbon atoms?

A)0.250 moles of glucose, C₆H₁₂O₆
B)1.20 moles of carbon dioxide, CO₂
C)0.500 moles of CaC₂
D)0.450 moles of Al₂(CO₃)₃
E)0.350 moles of C₄H₈O₂S

Question 39

Which contains the greatest number of hydrogen atoms?

A)0.300 moles of ammonia, NH₃
B)0.080 moles of sucrose, C₁₂H₂₂O₁₁
C)0.500 moles of ethanol, C₂H₅OH
D)0.250 moles of glucose, C₆H₁₂O₆
E)1.30 moles of water, H₂O

Question 40

A sample of (N₂H₅)₂C₃H₄O₄ contains 1.084 × 10²⁴ carbon atoms. How many moles of hydrogen atoms are in the sample? Hint: You can't convert directly between atoms of carbon and moles of hydrogen, use an intermediary unit.

A)4.200 moles
B)4.725 moles
C)7.000 moles
D)8.400 moles
E)2.400 moles

Question 41

A sample of sulfolane, C₄H₈O₂S, contains 5.00 × 10²⁴ atoms. How many moles of sulfolane are in the sample?

A)0.120 moles
B)0.554 moles
C)1.81 moles
D)8.30 moles
E)3.33 × 10²³ moles

Question 42

A sample of trifluoromethanesulfonic acid, CHF₃O₃S, contains 4.62 × 10²³ oxygen atoms. How many moles of CHF₃O₃S are in the sample? Hint: You can't convert directly between atoms of oxygen and moles of CHF₃O₃S, use an intermediary unit.

A)0.256 moles
B)2.30 moles
C)0.259 moles
D)0.767 moles
E)1.53 × 10²³ moles

Question 43

A sample of C₇H₅N₃O₄ contains 0.4662 moles of carbon atoms. How many nitrogen atoms are in the sample? Hint: You can't convert directly between moles of carbon atoms and atoms of nitrogen, use an intermediary unit.

A)2.807 × 10²³ atoms
B)1.203 × 10²³ atoms
C)4.101 × 10²³ atoms
D)1.998 × 10²² atoms
E)6.551 × 10²³ atoms

Question 44

How many hydrogen atoms are in 100.00 grams of water (H₂O)? Hint: Use moles as an intermediary unit and keep in mind you need to find hydrogen atoms.

A)2
B)200
C)11.10
D)6.681 × 10²⁴
E)3.340 × 10²⁴

Question 45

How many oxygen atoms are in 3.62 g of fructose, C₆H₁₂O₆? Hint: Use moles as an intermediary unit and keep in mind you need to find oxygen atoms.

A)1.56 × 10²¹
B)7.26 × 10²²
C)3.45 × 10²⁴
D)1.95 × 10²³
E)6.44 × 10²⁰

Question 46

How many grams of oxygen are needed to combine with 0.85 g of carbon in chlorophyll, C₅₅H₇₂MgN₄O₅? Hint: Use moles as an intermediary unit and focus on the ratio of carbon to oxygen in the formula.

A)1.56 × 10²¹ g
B)0.10 g
C)0.85 g
D)1.5 g
E)6.4 g

Question 47

How many grams of carbon are required to combine with 1.99 g of oxygen in C₂H₅OH? Hint: Use moles as an intermediary unit and focus on the ratio of carbon to oxygen in the formula.

A)5.99 g
B)4.99 g
C)1.99 g
D)2.99 g
E)3.99 g

Question 48

A sample of C₇H₅N₃O₄ has a mass of 7.81 g. What is the mass of oxygen in this sample? Hint: Use moles as an intermediary unit and focus on the ratio of how many oxygens there are per formula unit.

A)31.2 g
B)2.56 g
C)3.20 × 10²³ g
D)64.0 g
E)1.75 g

Question 49

What is the percent, by mass, of calcium in Ca(OCl)₂?

A)28.030%
B)28.571%
C)31.562%
D)43.787%
E)44.493%

Question 50

What is the percent, by mass, of chromium in K₂CrO₄?

A)26.776 %
B)31.763 %
C)40.268 %
D)42.241 %
E)51.996 %

Question 51

What is the percent, by mass, of tungsten in W(CH₃)₆?

A)4.3819 %
B)26.292 %
C)67.083 %
D)28.502 %
E)35.722 %

Question 52

What is the percent, by mass, of boron in Al(BF₄)₃?

A)9.501 %
B)9.385 %
C)10.152 %
D)11.285 %
E)23.713 %

Question 53

What is the percent, by mass, of oxygen in NiSO₄.7H₂O?

A)14.846 %
B)39.875 %
C)43.273 %
D)49.531 %
E)62.661 %

Question 54

What is the percent, by mass, of nitrogen in NH₃?

A)93.29 %
B)5.92 %
C)82.25 %
D)25.00 %
E)7.20 %

Question 55

How many grams of nitrogen are present in 100.0 g of NH₃?

A)93.29 g
B)5.92 g
C)82.25 g
D)25.00 g
E)7.20 g

Question 56

Which one of the following is definitely not an empirical formula?

A)C₁₂H₁₆O₃
B)C₁₂H₂₂O₁₁
C)C₃H₈O₂
D)C₄H₁₂N₂O
E)C₆H₁₂O₄

Question 57

Which one of the following is definitely not an empirical formula?

A)NH₃
B)N₂H₄
C)Al(NO₃)₃
D)H₃PO₄
E)H₂O

Question 58

A compound has an empirical formula of CH₂O. An independent analysis gave a value of 150.13 g for its molar mass. What is the molecular formula of the compound?

A)C₅H₁₀O₅
B)C₆H₁₂O₆
C)C₁₁H₂O
D)C₆H₆O₈
E)C₉H₁₀O₂

Question 59

A compound has an empirical formula of C₂H₄O. An independent analysis gave a value of 132 g for its molar mass. What is the molecular formula of the compound?

A)C₄H₄O₅
B)C₁₀H₁₂
C)C₇O₃
D)C₆H₁₂O₃
E)C₄H₈O₅

Question 60

A compound has an empirical formula of CH₂. An independent analysis gave a value of 70 g for its molar mass. What is the molecular formula of the compound?

A)C₂H₄
B)C₃H₆
C)C₄O₈
D)C₅H₁₀
E)C₅H₁₁

Question 61

A compound has an empirical formula of CH₂Cl. An independent analysis gave a value of 99.0 g for its molar mass. What is the molecular formula of the compound?

A)CH₂Cl
B)C₂H₄Cl₂
C)C₂H₂Cl₄
D)C₃H₆Cl₃
E)C₃H₃Cl₆

Question 62

A compound has an empirical formula of CHCl. An independent analysis gave a value of 194 g for its molar mass. What is the molecular formula of the compound?

A)CHCl
B)C₂H₂Cl₂
C)C₃H₃Cl₃
D)C₄H₄Cl₄
E)C₄H₃Cl₄

Question 63

A 7.300 gram sample of aluminum was quantitatively combined with a sample of selenium to form a compound. The compound had a mass of 39.35 grams. What is the empirical formula for the compound?

A)AlSe
B)Al₂Se
C)AlSe₂
D)Al₂Se₃
E)Al₃Se₂

Question 64

Magnetite is a binary compound containing only iron and oxygen. The percent, by weight, of iron is 72.360%. What is the empirical formula of magnetite?

A)FeO
B)FeO₂
C)Fe₃O₄
D)Fe₂O₃
E)Fe₂O₅

Question 65

A 6.789 g sample of a hydrocarbon, upon combustion analysis, yielded 9.883 grams of carbon dioxide. What is the percent, by mass, of carbon in the hydrocarbon?

A)18.75 %
B)39.73 %
C)68.69 %
D)45.57 %
E)34.44 %

Question 66

The empirical formula for a compound was determined to be C₂H₃O₂. Which of the following could be the molecular formula for the compound?

A)C₂H₆O₂
B)C₄H₆O₂
C)C₃H₄O₃
D)C₆H₉O₆
E)C₈H₁₀O₈

Question 67

A 6.987 g sample of a hydrocarbon, upon combustion analysis, yielded 8.398 grams of carbon dioxide. What is the percent, by mass, of carbon in the hydrocarbon?

A)16.01 %
B)23.66 %
C)32.80 %
D)34.91 %
E)58.68 %

Question 68

A 4.626 g sample of a hydrocarbon, upon combustion analysis, yielded 6.527 grams of water. What is the percent, by mass, of hydrogen in the hydrocarbon?

A)14.11 %
B)15.79 %
C)41.09 %
D)66.22 %
E)85.89 %

Question 69

A 4.266 g sample of a hydrocarbon, upon combustion analysis, yielded 5.672 grams of water. What is the percent, by mass, of hydrogen in the hydrocarbon?

A)7.44 %
B)8.62 %
C)14.88 %
D)17.24 %
E)20.07 %

Question 70

A 6.789 g sample of a hydrocarbon, upon combustion analysis, yielded 6.527 grams of water. What is the percent, by mass, of hydrogen in the hydrocarbon?

A)9.615 %
B)10.76 %
C)28.00 %
D)38.72 %
E)58.53 %

Question 71

A 6.789 g sample of a compound was analyzed for nitrogen. In the procedure, all of the nitrogen present was completely converted to ammonia (NH₃). 1.637 grams of ammonia were obtained. What is the percent, by mass, of nitrogen in the compound?

A)35.57 %
B)24.11 %
C)75.89 %
D)31.77 %
E)19.83 %

Question 72

A 7.689 g sample of a compound was analyzed for nitrogen. In the procedure, all of the nitrogen present was completely converted to ammonia (NH₃). 1.763 grams of ammonia were obtained. What is the percent, by mass, of nitrogen in the compound?

A)4.07 %
B)14.97 %
C)17.51 %
D)18.86 %
E)22.93 %

Question 73

A 4.927 g sample of a compound was analyzed for nitrogen. In the procedure, all of the nitrogen present was completely converted to ammonia (NH₃). 1.369 grams of ammonia were obtained. What is the percent, by mass, of nitrogen in the compound?

A)27.79 %
B)38.48 %
C)22.85 %
D)61.52 %
E)36.71 %

Question 74

A 7.294 g sample of a compound was analyzed for nitrogen. In the procedure, all of the nitrogen present was completely converted to ammonia (NH₃). 3.196 grams of ammonia were obtained. What is the percent, by mass, of nitrogen in the compound?

A)7.78 %
B)33.17 %
C)36.04 %
D)43.82 %
E)44.16 %

Question 75

A 3.06 gram sample of an unknown hydrocarbon with empirical formula CH₂O was found tocontain 0.0170 moles of the substance. What are the molecular mass and molecular formula, respectively, of the compound?

A)1.80 × 10² g/mol, C₆H₁₂O₆
B)30.1 g/mol, CH₂O
C)5.42 × 10³ g/mol, C₃₀H₆₀O₃₀
D)3.06 g/mol, CH₂O
E)1.80 × 10² g/mol, CH₂O

Question 76

A compound contains arsenic and oxygen as its only elements. A 1.626 g sample of the compound contains 1.060 g of arsenic. What is the empirical formula of the compound?

A)As₂O
B)AsO
C)As₂O₃
D)AsO₂
E)As₂O₅

Question 77

A compound contains arsenic and oxygen as its only elements. A 1.626 g sample of the compound contains 1.232 g of arsenic. What is the empirical formula of the compound?

A)As₂O
B)AsO
C)As₂O₃
D)AsO₂
E)As₂O₅

Question 78

A compound contains carbon, hydrogen, and nitrogen as its only elements. A 9.353 g sample of the compound contains 5.217 g of carbon and 1.095 g of hydrogen; the remainder of the mass is nitrogen. What is the empirical formula of the compound? Hint: Use moles to relate the mass of one element to another.

A)C₂H₅N
B)C₃H₅N
C)C₃H₆N
D)C₃H₇N
E)C₄H₉N₂

Question 79

A compound contains sodium, boron, and oxygen. An experimental analysis gave values of 53.976 % sodium and 8.461 % boron, by weight; the remainder of the mass is oxygen. What is the empirical formula of the compound? Hint: Assume you have 100 grams of this substance and use moles to relate the mass of one element to another.

A)NaBO₂
B)Na₃BO₃
C)Na₃BO₂
D)NaB₃O
E)Na₃B₃O₈

Question 80

A compound contains potassium, nitrogen, and oxygen. An experimental analysis gave values of 45.942 % potassium and 16.458 % nitrogen, by weight; the remainder is oxygen. What is the empirical formula of the compound? Hint: Assume you have 100 grams of this substance and use moles to relate the mass of one element to another.

A)KNO₂
B)KNO₃
C)K₂N₂O₅
D)KN₃O₈
E)K₂N₂O