Deck 3: Stoichiometry: Calculations With Chemical Formulas and Equations

Question 1

The reaction used to inflate automobile airbags ________.

A)produces sodium gas
B)is a combustion reaction
C)is a combination reaction
D)violates the law of conservation of mass
E)is a decomposition reaction

Answer 1

is a decomposition reaction

Question 2

The formula weight of magnesium fluoride (MgF₂), rounded to one decimal place, is ________ amu.

A)86.6
B)43.3
C)62.3
D)67.6
E)92.9

Answer 2

62.3

Question 3

The formula weight of a substance is ________.

A)identical to the molar mass
B)the same as the percent by mass weight
C)determined by combustion analysis
D)the sum of the atomic weights of each atom in its chemical formula
E)the weight of a sample of the substance

Answer 3

the sum of the atomic weights of each atom in its chemical formula

Question 4

The formula weight of potassium dichromate (K₂Cr₂O₇ )is ________ amu.

A)107.09
B)255.08
C)242.18
D)294.18
E)333.08

Question 5

Which one of the following substances is the product of this combination reaction? Al (s) + I₂ (s) → ________

A)AlI₂
B)AlI
C)AlI₃
D)Al₂I₃
E)Al₃I₂

Question 6

The formula of nitrobenzene is C₆H₅NO₂. The molecular weight of this compound is ________ amu.

A)107.11
B)43.03
C)109.10
D)123.11
E)3.06

Question 7

Which of the following are combination reactions? 1) CH₄ (g) + O₂ (g) → CO₂ (g) + H₂O (l)
2) CaO (s) + CO₂ (g) → CaCO₃ (s)
3) Mg (s) + O₂ (g) → MgO (s)
4) PbCO₃ (s) → PbO (s) + CO₂ (g)

A)1, 2, and 3
B)2 and 3
C)1, 2, 3, and 4
D)4 only
E)2, 3, and 4

Question 8

When a hydrocarbon burns in air, a component produced is ________.

A)oxygen
B)nitrogen
C)carbon
D)water
E)argon

Question 9

When the following equation is balanced, the coefficients are ________. C₈H₁₈ + O₂ → CO₂ + H₂O

A)2, 3, 4, 4
B)1, 4, 8, 9
C)2, 12, 8, 9
D)4, 4, 32, 36
E)2, 25, 16, 18

Question 10

Of the reactions below, which one is a decomposition reaction?

A)NH₄Cl → NH₃ + HCl
B)2Mg + O₂ → 2MgO
C)2N₂ + 3H₂ → 2NH₃
D)2CH₄ + 4O₂ → 2CO₂ + 4H₂O
E)Cd(NO₃)₂ + Na₂S → CdS + 2NaNO₃

Question 11

Which of the following are decomposition reactions? 1) CH₄ (g) + O₂ (g) → CO₂ (g) + H₂O (l)
2) CaO (s) + CO₂ (g) → CaCO₃ (s)
3) Mg (s) + O₂ (g) → MgO (s)
4) PbCO₃ (s) → PbO (s) + CO₂ (g)

A)1, 2, and 3
B)4 only
C)1, 2, 3, and 4
D)2 and 3
E)2, 3, and 4

Question 12

Which of the following are combustion reactions? 1) CH₄ (g) + O₂ (g) → CO₂ (g) + H₂O (l)
2) CaO (s) + CO₂ (g) → CaCO₃ (s)
3) PbCO₃ (s) → PbO (s) + CO₂ (g)
4) CH₃OH (l) + O₂ (g) → CO₂ (g) + H₂O (l)

A)1 and 4
B)1, 2, 3, and 4
C)1, 3, and 4
D)2, 3, and 4
E)3 and 4

Question 13

When a hydrocarbon burns in air, what component of air reacts?

A)oxygen
B)nitrogen
C)carbon dioxide
D)water
E)argon

Question 14

Which one of the following is not true concerning automotive air bags?

A)They are inflated as a result of a decomposition reaction.
B)They are loaded with sodium azide initially.
C)The gas used for inflating them is oxygen.
D)The two products of the decomposition reaction are sodium and nitrogen.
E)A gas is produced when the air bag activates.

Question 15

The molecular weight of the acetic acid (CH₃CO₂H), rounded to the nearest integer, is ________ amu.

A)60
B)48
C)44
D)32

Question 16

The formula weight of lead nitrate (Pb(NO₃)₂)is ________ amu.

A)269.2
B)285.2
C)317.2
D)331.2
E)538.4

Question 17

The formula weight of calcium nitrate (Ca(NO₃)₂), rounded to one decimal place, is ________ amu.

A)102.1
B)164.0
C)204.2
D)150.1
E)116.1

Question 18

The formula weight of silver chromate (Ag₂CrO₄)is ________ amu.

A)159.87
B)223.87
C)331.73
D)339.86
E)175.87

Question 19

Of the reactions below, which one is not a combination reaction?

A)C + O₂ → CO₂
B)2Mg + O₂ → 2MgO
C)2N₂ + 3H₂ → 2NH₃
D)CaO + H₂O → Ca(OH)₂
E)2CH₄ + 4O₂ → 2CO₂ + 4H₂O

Question 20

The formula weight of ammonium sulfate ((NH₄)₂SO₄), rounded to the nearest integer, is ________ amu.

A)100
B)118
C)116
D)132
E)264

Question 21

The mass % of H in methane (CH₄)is ________.

A)25.13
B)4.032
C)74.87
D)92.26
E)7.743

Question 22

How many atoms of nitrogen are in 10 g of NH₄NO₃?

A)3.5
B)1.5 × 10²³
C)3.0 × 10²³
D)1.8
E)2

Question 23

The mass % of C in methane (CH₄)is ________.

A)25.13
B)133.6
C)74.87
D)92.26
E)7.743

Question 24

Gaseous argon has a density of 1.40 g/L at standard conditions. How many argon atoms are in 1.00 L of argon gas at standard conditions?

A)4.76 × 10²²
B)3.43 × 10²⁵
C)2.11 × 10²²
D)1.59 × 10²⁵
E)6.02 × 10²³

Question 25

How many oxygen atoms are contained in 2.74 g of Al₂(SO₄)₃?

A)12
B)6.02 × 10²³
C)7.22 × 10²⁴
D)5.79 × 10²²
E)8.01 × 10^-3

Question 26

How many molecules of CH₄ are in 48.2 g of this compound?

A)5.00 × 10²⁴
B)3.00
C)2.90 × 10²⁵
D)1.81 × 10²⁴
E)4.00

Question 27

A 30.5 gram sample of glucose (C₆H₁₂O₆)contains ________ mol of glucose.

A)0.424
B)0.169
C)5.90
D)2.36
E)0.136

Question 28

A sample of CH₂F₂ with a mass of 19 g contains ________ atoms of F.

A)2.2 × 10²³
B)38
C)3.3 × 10²⁴
D)4.4 ×10²³
E)9.5

Question 29

One mole of ________ contains the smallest number of atoms.

A)S₈
B)C₁₀H₈
C)Al₂(SO₄)₃
D)Na₃PO₄
E)NaCl

Question 30

One million argon atoms is ________ mol (rounded to two significant figures)of argon atoms.

A)3.0
B)1.7 × 10^-18
C)6.0 × 10²³
D)1.0 × 10^-6
E)1.0 × 10⁶

Question 31

Calculate the percentage by mass of oxygen in Pb(NO₃)₂.

A)9.7
B)14.5
C)19.3
D)29.0
E)33.4

Question 32

A sample of CH₄O with a mass of 32.0 g contains ________ molecules of CH₄O.

A)5.32 × 10^-23
B)1.00
C)1.88 × 10²²
D)6.02 × 10²³
E)32.0

Question 33

Calculate the percentage by mass of nitrogen in PtCl₂(NH₃)₂.

A)4.67
B)9.34
C)9.90
D)4.95
E)12.67

Question 34

Calculate the percentage by mass of hydrogen in PtCl₂(NH₃)₂.

A)1.558
B)1.008
C)0.672
D)0.034
E)2.016

Question 35

One mole of ________ contains the largest number of atoms.

A)S₈
B)C₁₀H₈
C)Al₂(SO₄)₃
D)Na₃PO₄
E)Cl₂

Question 36

Calculate the percentage by mass of lead in PbCO₃.

A)17.96
B)22.46
C)73.05
D)77.54
E)89.22

Question 37

Calculate the percentage by mass of chlorine in PtCl₂(NH₃)₂.

A)23.63
B)11.82
C)25.05
D)12.53
E)18.09

Question 38

The total number of atoms in 0.111 mol of Fe(CO)₃(PH₃)₂ is ________.

A)15.0
B)1.00 × 10²⁴
C)4.46 × 10²¹
D)1.67
E)2.76 × 10^-24

Question 39

Calculate the percentage by mass of lead in Pb(NO₃)₂.

A)38.6
B)44.5
C)62.6
D)65.3
E)71.2

Question 40

The mass % of F in the binary compound KrF₂ is ________.

A)18.48
B)45.38
C)68.80
D)81.52
E)31.20

Question 41

A nitrogen oxide is 63.65% by mass nitrogen. The molecular formula could be ________.

A)NO
B)NO₂
C)N₂O
D)N₂O₄
E)either NO₂ or N₂O₄

Question 42

When the following equation is balanced, the coefficient of H₂O is ________. Ca (s) + H₂O (l) → Ca(OH)₂ (aq) + H₂ (g)

A)1
B)2
C)3
D)5
E)4

Question 43

When the following equation is balanced, the coefficient of Al is ________. Al (s) + H₂O (l) → Al(OH)₃ (s) + H₂ (g)

A)1
B)2
C)3
D)5
E)4

Question 44

The molecular formula of aspartame, the generic name of NutraSweet^®, is C₁₄H₁₈N₂O₅. The molar mass of aspartame, rounded to the nearest integer, is ________ g.

A)24
B)156
C)294
D)43
E)39

Question 45

How many moles of sodium carbonate contain 1.773 × 10¹⁷ carbon atoms?

A)5.890 × 10^-7
B)2.945 × 10^-7
C)1.473 × 10^-7
D)8.836 × 10^-7
E)9.817 × 10^-8

Question 46

Which hydrocarbon pair below has identical mass percentage of C?

A)C₃H₄ and C₃H₆
B)C₂H₄ and C₃H₄
C)C₂H₄ and C₄H₂
D)C₂H₄ and C₃H₆
E)none of the above

Question 47

When the following equation is balanced, the coefficient of H₂ is ________. K (s) + H₂O (l) → KOH (aq) + H₂ (g)

A)1
B)2
C)3
D)4
E)5

Question 48

How many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide?

A)1.08 × 10²³
B)6.02 × 10²⁴
C)1.80 × 10²⁴
D)1.08 × 10²⁴
E)6.02 × 10²³

Question 49

When the following equation is balanced, the coefficients are ________. NH₃ (g) + O₂ (g) → NO₂ (g) + H₂O (g)

A)1, 1, 1, 1
B)4, 7, 4, 6
C)2, 3, 2, 3
D)1, 3, 1, 2
E)4, 3, 4, 3

Question 50

When the following equation is balanced, the coefficient of H₂S is ________. FeCl₃ (aq) + H₂S (g) → Fe₂S₃ (s) + HCl (aq)

A)1
B)2
C)3
D)5
E)4

Question 51

How many carbon atoms are there in 52.06 g of carbon dioxide?

A)5.206 × 10²⁴
B)3.134 × 10²⁵
C)7.122 × 10²³
D)8.648 × 10^-23
E)1.424 × 10²⁴

Question 52

When the following equation is balanced, the coefficients are ________. Al(NO₃)₃ + Na₂S → Al₂S₃ + NaNO₃

A)2, 3, 1, 6
B)2, 1, 3, 2
C)1, 1, 1, 1
D)4, 6, 3, 2
E)2, 3, 2, 3

Question 53

When the following equation is balanced, the coefficient of Al₂O₃ is ________. Al₂O₃ (s) + C (s) + Cl₂ (g) → AlCl₃ (s) + CO (g)

A)1
B)2
C)3
D)4
E)5

Question 54

How many oxygen atoms are there in 52.06 g of carbon dioxide?

A)1.424 × 10²⁴
B)6.022 × 10²³
C)1.204 × 10²⁴
D)5.088 × 10²³
E)1.018 × 10²⁴

Question 55

How many grams of sodium carbonate contain 1.773 × 10¹⁷ carbon atoms?

A)3.121 × 10^-5
B)1.011 × 10^-5
C)1.517 × 10^-5
D)9.100 × 10^-5
E)6.066 × 10^-5

Question 56

A sulfur oxide is 50.0% by mass sulfur. This molecular formula could be ________.

A)SO
B)SO₂
C)S₂O
D)S₂O₄
E)either SO₂ or S₂O₄

Question 57

The compound responsible for the characteristic smell of garlic is allicin, C₆H₁₀OS₂. The mass of 1.00 mol of allicin, rounded to the nearest integer, is ________ g.

A)34
B)162
C)86
D)61
E)19

Question 58

Propane (C₃H₈)reacts with oxygen in the air to produce carbon dioxide and water. In a particular experiment, 38.0 grams of carbon dioxide are produced from the reaction of 22.05 grams of propane with excess oxygen. What is the % yield in this reaction?

A)38.0
B)57.6
C)66.0
D)86.4
E)94.5

Question 59

There are ________ oxygen atoms in 30 molecules of C₂₀H₄₂S₃O₂.

A)6.0 × 10²³
B)1.8 × 10²⁵
C)3.6 × 10²⁵
D)1.2 × 10²⁴
E)60

Question 60

How many sulfur dioxide molecules are there in 0.180 mol of sulfur dioxide?

A)1.80 × 10²³
B)6.02 × 10²⁴
C)6.02 × 10²³
D)1.08 × 10²⁴
E)1.08 × 10²³

Question 61

When the following equation is balanced, the coefficient of C₃H₈O₃ is ________. C₃H₈O₃ (g) + O₂ (g) → CO₂ (g) + H₂O (g)

A)1
B)2
C)3
D)7
E)5

Question 62

When the following equation is balanced, the coefficient of water is ________. K (s) + H₂O (l) → KOH (aq) + H₂ (g)

A)1
B)2
C)3
D)4
E)5

Question 63

When the following equation is balanced, the coefficient of O₂ is ________. C₂H₄O (g) + O₂ (g) → CO₂ (g) + H₂O (g)

A)2
B)3
C)4
D)5
E)1

Question 64

There are ________ mol of carbon atoms in 4 mol of C₄H₈O₂.

A)4
B)8
C)16
D)20
E)32

Question 65

When the following equation is balanced, the coefficient of oxygen is ________. PbS (s) + O₂ (g) → PbO (s)+ SO₂ (g)

A)1
B)3
C)2
D)4
E)5

Question 66

Write the balanced equation for the reaction that occurs when methanol, CH₃OH (l), is burned in air. What is the coefficient of oxygen in the balanced equation?

A)1
B)2
C)3
D)4
E)3/2

Question 67

The balanced equation for the decomposition of sodium azide is ________.

A)2NaN₃ (s) → 2Na (s) + 3N₂ (g)
B)2NaN₃ (s) → Na₂ (s) + 3N₂ (g)
C)NaN₃ (s) → Na (s) + N₂ (g)
D)NaN₃ (s) → Na (s) + N₂ (g) + N (g)
E)2NaN₃ (s) → 2Na (s) + 2N₂ (g)

Question 68

When the following equation is balanced, the coefficient of HNO₃ is ________. HNO₃ (aq) + CaCO₃ (s) → Ca(NO₃)₂ (aq) + CO₂ (g) + H₂O (l)

A)1
B)2
C)3
D)5
E)4

Question 69

Predict the product in the combination reaction below. Al (s) + N₂ (g) → ________

A)AlN
B)Al₃N
C)AlN₂
D)Al₃N₂
E)AlN₃

Question 70

When the following equation is balanced, the coefficient of H₂ is ________. CO (g) + H₂ (g) → H₂O (g) + CH₄ (g)

A)1
B)2
C)3
D)4
E)0

Question 71

When the following equation is balanced, the coefficient of water is ________. N₂O₅ (g) + H₂O (l) → HNO₃ (aq)

A)5
B)2
C)3
D)4
E)1

Question 72

When the following equation is balanced, the coefficient of nitric acid is ________. N₂O₅ (g) + H₂O (l) → HNO₃ (aq)

A)5
B)2
C)3
D)4
E)1

Question 73

Write the balanced equation for the reaction that occurs when methanol, CH₃OH (l), is burned in air. What is the coefficient of methanol in the balanced equation?

A)1
B)2
C)3
D)4
E)3/2

Question 74

When the following equation is balanced, the coefficient of hydrogen is ________. K (s) + H₂O (l) → KOH (aq) + H₂ (g)

A)1
B)2
C)3
D)4
E)5

Question 75

When the following equation is balanced, the coefficient of H₃PO₄ is ________. H₃PO₄ (aq) + NaOH (aq) → Na₃PO₄ (aq) + H₂O (l)

A)1
B)2
C)3
D)4
E)0

Question 76

When the following equation is balanced, the coefficient of H₂SO₄ is ________. H₂SO₄ (aq) + NaOH (aq) → Na₂SO₄ (aq) + H₂O (l)

A)1
B)2
C)3
D)4
E)0.5

Question 77

When the following equation is balanced, the coefficient of HCl is ________. CaCO₃ (s) + HCl (aq) → CaCl₂ (aq) + CO₂ (g) + H₂O (l)

A)1
B)2
C)3
D)4
E)0

Question 78

What is the coefficient of O₂ when the following equation is completed and balanced? C₄H₈O₂ + O₂ → ________

A)2
B)3
C)5
D)6
E)1

Question 79

When the following equation is balanced, the coefficient of sulfur dioxide is ________. PbS (s) + O₂ (g) → PbO (s) + SO₂ (g)

A)5
B)1
C)3
D)2
E)4

Question 80

When the following equation is balanced, the coefficient of dinitrogen pentoxide is ________. N₂O₅ (g) + H₂O (l) → HNO₃ (aq)

A)1
B)2
C)3
D)4
E)5