Deck 10: Chemical Calculations Involving Chemical Equations

Question 1

Indicate the missing words in the following statement: "For an ordinary chemical reaction the mass of the products is ________ the mass of the reactants."

A) always less than
B) usually more than
C) always equal to
D) usually less than

Answer 1

always equal to

Question 2

Which of the following elements is represented by a diatomic molecule in a chemical equation?

A) krypton
B) beryllium
C) chlorine
D) boron

Answer 2

chlorine

Question 3

In a valid chemical equation, ________.

A) the number of products must equal the number of reactants
B) the reactants always appear on the right-hand side of the equation
C) only reactants and products that are solids or liquids are listed
D) the total number of atoms on each side of the equation must be equal

Answer 3

the total number of atoms on each side of the equation must be equal

Question 4

Which of the following equations is not balanced?

A) 2Mg + O₂ $\rightarrow$ 2MgO
B) CaCO₃ $\rightarrow$ CaO + CO₂
C) 2NO + O₂ $\rightarrow$ 2NO₂
D) 2NaHCO₃ + H₂SO₄ $\rightarrow$ Na₂SO₄ + 2H₂O + CO₂

Question 5

Which of the following reactions is correctly balanced?

A) Zn + 2 HCl $\rightarrow$ H₂ + ZnCl₂
B) 2 H₂O + C $\rightarrow$ CO + 2 H₂
C) N₂ + H₂ $\rightarrow$ 2 NH₃
D) CO + O₂ $\rightarrow$ CO₂

Question 6

Indicate which set of coefficients balances the equation:
_____ NH₃ + _____ O₂ $\rightarrow$ _____ NO + _____ H₂O

A) 3, 2, 1, 3
B) 6, 5, 4, 4
C) 2, 6, 3, 2
D) 4, 5, 4, 6

Question 7

Balance the following equation. What is the sum of the coefficients?
_____ P₄ + _____ S₈ $\rightarrow$ _____ P₄S₁₀

A) 12
B) 19
C) 14
D) 13

Question 8

When the equation C₈H₁₈ + O₂ $\rightarrow$ CO₂ + H₂O is correctly balanced, the coefficient in front of O₂ is ________.

A) 25
B) 12
C) 16
D) 18

Question 9

What is the coefficient for CO₂ when the equation for the combustion of methanol is balanced?
_____ CH₃OH + _____ O₂ $\rightarrow$ _____ CO₂ + _____ H₂O

A) 1.5
B) 4
C) 2
D) 6

Question 10

In the reaction below, which species is present in the solid state?
CaCO₃ (s) + 2HNO₃ (aq) $\rightarrow$ Ca(NO₃)₂ (aq) + H₂O (l)+ CO₂ (g)

A) H₂O
B) CO₂
C) CaCO₃
D) HNO₃

Question 11

Which of the following reactions is a synthesis reaction?

A) SO₃ + H₂O $\rightarrow$ H₂SO₄
B) C₃H₈ + 5 O₂ $\rightarrow$ 3CO₂ + 4H₂O
C) 3CuSO₄ + Al $\rightarrow$ Al₂(SO₄)₃ + 3Cu
D) 2NaHCO₃ $\rightarrow$ Na₂CO₃ + CO₂ + H₂O

Question 12

Which of the following reactions is incorrectly classified?

A) 2 NO₂ + H₂O₂ $\rightarrow$ 2 HNO₃ (synthesis)
B) Fe + CuSO₄ $\rightarrow$ Cu + FeSO₄ (single-replacement)
C) F₂ + 2NaCl $\rightarrow$ Cl₂ + 2 NaF (single-replacement)
D) BaCl₂ + H₂SO₄ $\rightarrow$ BaSO₄ + 2 HCl (single-replacement)

Question 13

Which of the following reactions below is a decomposition reaction?

A) C₇H₈O₂ (l) + 8 O₂ (g) $\rightarrow$ 7 CO₂ (g) + 4 H₂O (l)
B) 2 KClO₃ (s) $\rightarrow$ 2 KCl (s) + 3 O₂ (g)
C) 2 Cr (s) + 3 Cl₂ (g) $\rightarrow$ 2 CrCl₃ (s)
D) 6 Li (s) + N₂ (g) $\rightarrow$ 2 Li₃N (s)

Question 14

Which of the following reactions is incorrectly classified?

A) Mg (s) + 2 HCl (aq) $\rightarrow$ MgCl₂ (aq) + H₂ (aq) single-replacement
B) Pb(NO₃)₂ (aq) + 2 LiCl (aq) $\rightarrow$ 2 LiNO₃ (aq) + PbCl₂ (s) double-replacement
C) NO₂ (g) + H₂O (g) $\rightarrow$ HNO₃ (g) synthesis
D) PbO (s) + C (s) $\rightarrow$ Pb (s) + CO (g) double-replacement

Question 15

Which of the following reactions is incorrectly classified?

A) Zn + H₂SO₄ $\rightarrow$ ZnSO₄ + H₂ single-replacement
B) 2 KClO₃ $\rightarrow$ 2 KCl + 3 O₂ decomposition
C) CH₄ + 2 O₂ $\rightarrow$ CO₂ + 2 H₂O single-replacement
D) AgNO₃ + KCl $\rightarrow$ KNO₃ + AgCl double-replacement

Question 16

Which one of the following conversion factors is not consistent with the equation?
4NH₃ + 5 O₂ $\rightarrow$ 4NO + 6H₂O

A)
B)
C)
D)

Question 17

Given: 2 N₂ + 5 O₂ $\rightarrow$ 2 N₂O₅
Which of the following is not a valid equality?

A) 5 mol O₂ = 2 mol N₂
B) 2 mol N₂O₅ = 2 mol N₂
C) 2 mol N₂ = 2 mol O₂
D) 5 mol O₂ = 2 mol N₂O₅

Question 18

How many moles of Al are needed to react exactly with 10.00 moles of Fe₂O₃ according to the following equation?
Fe₂O₃ + 2 Al $\rightarrow$ Al₂O₃ + 2Fe

A) 15.0 moles
B) 20.0 moles
C) 30.0 moles
D) 60.0 moles

Question 19

Given the following equation, 2 N₂ + 5 O₂ $\rightarrow$ 2 N₂O₅, 1.25 moles of nitrogen requires ________ moles of oxygen.

A) 0.500
B) 1.75
C) 3.13
D) 1.56

Question 20

How many moles of CO₂ will be produced from the complete combustion of 0.956 moles of C₇H₁₆ in the reaction below?
C₇H₁₆ + 11 O₂ $\rightarrow$ 7 CO₂ + 8 H₂O

A) 0.667 mole
B) 3.50 moles
C) 1.85 moles
D) 6.69 moles

Question 21

Given: 2 Na + O₂ $\rightarrow$ Na₂O₂
Calculate the moles of sodium peroxide (Na₂O₂) produced if 32.5 g of sodium reacts with excess oxygen.

A) 27.6 mol
B) 55.1 mol
C) 0.354 mol
D) 0.707 mol

Question 22

Which of the following is the correct "set-up" for the problem "How many grams of H₂O will be produced from 3.2 moles of O₂ and an excess of H₂S?" according to the reaction:
2H₂S + 3 O₂ $\rightarrow$ 2H₂O + 2SO₂

A)
B)
C)
D)

Question 23

The "set-up" below for the problem "How many grams of SO₂ will be produced from 10.0 g of S₈ and an excess of O_2?" according to the reaction:
S₈ + 8 O₂ $\rightarrow$ 8 SO₂
Is correct except the letters A and B have replaced the numbers in one of the conversion factors. What are the numerical values of A and B, respectively?

A) 8 and 8
B) 1 and 8
C) 8 and 1
D) 1 and 1

Question 24

In the following reaction, how many grams of H₂O are produced if 3.65 g of N₂H₄ react?
N₂H₄ + 3 O₂ $\rightarrow$ 2NO₂ + 2H₂O

A) 4.10 g
B) 11.2 g
C) 10.5 g
D) 1.47 g

Question 25

For the reaction: 2 P + 3 Cl₂ $\rightarrow$ 2 PCl₃, if 32.5 g of Cl₂ reacts completely with excess P, how many grams of PCl₃ will be produced?

A) 42.0 g
B) 62.9 g
C) 83.9 g
D) 94.4 g

Question 26

In the reaction: 4HPO₃ + 12C $\rightarrow$ 2H₂ + 12CO + P₄, how many molecules of CO are produced when 5.00 moles of HPO₃ react?

A) 4.11 x 10²³ molecules
B) 1.64 x 10²⁴ molecules
C) 9.03 x 10²⁴ molecules
D) 1.97 x 10²⁵ molecules

Question 27

How many moles of H₂O will be produced if 6.80 x 10²⁴ formula units of NH₄NO₃ are decomposed in the reaction given below?
NH₄NO₃ $\rightarrow$ N₂O + 2H₂O

A) 0.876 mole
B) 3.30 moles
C) 5.40 moles
D) 22.6 moles

Question 28

Aspirin (C₉H₈O₄) can be made in the laboratory by reacting salicylic acid (C₇H₆O₃) with acetyl chloride (C₂H₃ClO).
C₇H₆O₃ + C₂H₃ClO $\rightarrow$ C₉H₈O₄ + HCl
What mass of HCl is produced by the complete reaction of 36.0 g of acetyl chloride?

A) 108 g
B) 16.7 g
C) 58.1 g
D) 8.69 g

Question 29

Propane (C₃H₈) burns in oxygen to form CO₂ and H₂O according to the following equation. How many grams of O₂ are required to burn 3.01 x 10²³ propane molecules?
C₃H₈ + 5 O₂ $\rightarrow$ 3 CO₂ + 4 H₂O

A) 80.0 g
B) 40.0 g
C) 160. g
D) 64.0 g

Question 30

If a mixture containing 0.50 moles of N₂ and 1.8 moles of H₂ is allowed to react according to the equation
N₂ + 3H₂ $\rightarrow$ 2NH₃

A) 17.0 grams of NH₃ can be produced.
B) N₂ is the limiting reactant.
C) H₂ is the limiting reactant.
D) Both A and B are correct.

Question 31

If a mixture containing an unlimited amount of A, 3.00 moles of B and 5.0 moles of C is allowed to react according to the equation
2A + 2B + 4C $\rightarrow$ 4D + 3E

A) A will be the limiting reactant.
B) B will be the limiting reactant.
C) C will be the limiting reactant.
D) Both A and C are the limiting reactants.

Question 32

How many moles of NO₂ can be produced from 14.0 g of NO and 4.00 g of O₂ according to the equation:
2 NO + O₂ $\rightarrow$ 2NO₂

A) 0.250 mole
B) 0.125 mole
C) 0.467 mole
D) 2.41 moles

Question 33

15.0 g of Cu are combined with 46.0 g of HNO₃ (molar mass = 63.02), according to the reaction:
3 Cu + 8 HNO₃ $\rightarrow$ 3 Cu(NO₃)₂ + 2 NO + 4 H₂
Which reactant is limiting, and how many grams of H₂ is produced?

A) Cu, 3.79 g
B) Cu, 0.629 g
C) HNO₃, 0.737 g
D) HNO₃, 6.13 g

Question 34

In making a banana split sundae, how many sundaes can be made from 3 dozen bananas, 2 gallons of ice cream and unlimited chocolate syrup using the "recipe" below? (1 gallon of ice cream = 25 scoops)
1 banana + 2 scoops of ice cream + 4 tsp chocolate syrup $\rightarrow$ 1 banana split sundae

A) 36
B) 20
C) 25
D) 15

Question 35

The brown color of smog is due to the presence of nitrogen dioxide, NO₂. Nitrogen monoxide (NO), a by-product of combustion of fossil fuels, reacts with oxygen to produce NO₂ in the atmosphere:
2 NO + O₂ $\rightarrow$ 2 NO₂
If 0.65 mole of NO is reacted with 0.75 mole of O₂ to produce NO₂, the limiting reactant is ________.

A) both NO and O₂
B) O₂
C) NO
D) Insufficient information is given to determine which species is the limiting reactant.

Question 36

If a mixture containing 0.80 mole of A, 2.1 moles of B, and 1.6 moles of C is allowed to react according to the equation:
2 A + 4 B + 3 C $\rightarrow$ 4 D + 2 E

A) A will be the limiting reactant.
B) B will be the limiting reactant.
C) Both A and B are the limiting reactants.
D) C will be the limiting reactant.

Question 37

If 30 slices of bread, 26 slices of cheese, and 38 slices of ham are available to make ham-cheese sandwiches according to the parameters given below, how many ham-cheese sandwiches can be prepared?
1 slice of ham + 2 slices of cheese + 2 slices of bread - 1 ham-cheese sandwich

A) 15
B) 16
C) 30
D) 13

Question 38

Carbon monoxide is reacted with oxygen and converted to carbon dioxide by the catalytic converter on automobiles:
2 CO(g) + O₂(g) $\rightarrow$ 2 CO₂(g)
Depicted below is a representation of a mixture of CO and O₂ in a catalytic converter (at the molecular level). The gray spheres represent oxygen atoms and the black spheres represent carbon atoms. For the mixture shown below, which species is the limiting reactant?

A) CO₂
B) CO
C) O₂
D) Insufficient information is given to determine.

Question 39

Tin metal is reacted with hydrochloric acid according to the following equation. 0.240 moles of Sn is reacted with 0.320 mol of HCl. Calculate the mass of hydrogen gas liberated by the reaction.
Sn + 2 HCl $\rightarrow$ H₂ + SnCl₂

A) 0.323 g
B) 2.79 g
C) 0.485 g
D) 1.31 g

Question 40

In a certain experiment 24.9 g of NH₄NO₃ (molar mass = 80.06) was produced from 27.2 g of Fe(NO₃)₃ (molar mass = 241.87) reacting with an excess of NH₃ and H₂O according to the equation
Fe(NO₃)₃ + 3 NH₃ + 3 H₂O $\rightarrow$ Fe(OH)₃ + 3 NH₄NO₃
What is, respectively, the theoretical yield and percent yield of NH₄NO₃?

A) 5.53 g and 42.1%
B) 13.5 g and 83.7%
C) 16.6 g and 31.7%
D) 27.0 g and 92.2%

Question 41

In a certain experiment using Ca and an excess of F, 10.6 g of CaF₂ is obtained. This represents a 76.4 percent yield. What is the theoretical yield of ZnS for this experiment?

A) 13.9 g
B) 12.6 g
C) 14.1 g
D) 15.7 g

Question 42

Which statement concerning yields is correct?

A) Percent yield is the ratio of the actual yield to the theoretical yield times 100%.
B) Theoretical yield is the difference between the calculated yield and the actual yield.
C) Actual yield is the calculated amount of product that can be obtained from a given reaction.
D) In most chemical reactions, the amount of product isolated is larger than the theoretically possible amount.

Question 43

To make a hot fudge sundae, you need 2 scoops of ice cream and 30 mL of hot fudge syrup. What is the percent yield if you make 13 sundaes from 1 gallon of ice cream and 500 mL of hot fudge syrup? (1 gallon of ice cream = 30 scoops)
2 scoops ice cream + 30 mL hot fudge syrup- 1 hot fudge sundae

A) 13%
B) 78%
C) 87%
D) 115%

Question 44

The astronauts of the Apollo 13 mission to the moon were almost lost in space due to the explosion of a valve on their primary oxygen generator. The lives of the astronauts were threatened by increasing concentrations of carbon dioxide in the spacecraft. Gaseous carbon dioxide(CO₂) be absorbed from the air in a spacecraft with open canisters that contain solid lithium hydroxide according to the following equation:
2 LiOH (s) + CO₂ (g) $\rightarrow$ Li₂CO₃ (s) + H₂O (l)
If a canister absorbed 225.0 grams of carbon dioxide from the air that resulted in the production of 66.30 grams of H₂O, what was the percent yield for H₂O?

A) 59.32%
B) 79.63%
C) 71.96%
D) 96.54%

Question 45

In the atmosphere, the air pollutant nitrogen dioxide (NO₂) reacts with water to produce nitric acid (HNO₃), a component of acid rain. The reaction for the formation of nitric acid is:
3 NO₂ (g) + H₂O (l) $\rightarrow$ 2 HNO₃ (aq) + NO (g)
If 8.50 moles of nitrogen dioxide reacts with excess water, what is the actual yield (in grams) of NO if the percent yield is 89.4%?

A) 57.8 g
B) 136 g
C) 85.0 g
D) 76.0 g

Question 46

Aluminum is produced commercially by high-temperature electrolysis of aluminum oxide. When 1.500 x 10³ g of Al₂O₃ is reacted with excess C, 601 g of Al is produced. Calculate the percent yield for the production of Al.
Al₂O₃(s) + 3 C(s) $\rightarrow$ 2 Al(s) + 3 CO(g)

A) 94.7%
B) 75.7%
C) 54.3%
D) 82.1%

Question 47

A mixture contains 0.75 moles of BaCO₃ and 0.55 moles of Li₂CO₃. When this mixture is strongly heated both carbonates completely decompose to oxides and carbon dioxide as shown by the equations:
BaCO₃ ? BaO + CO₂
Li₂CO₃ $\rightarrow$ Li₂O + CO₂
How many moles of CO₂ are produced from the decomposition?

A) 1.30 moles
B) 1.60 moles
C) 0.75 mole
D) 0.65 mole

Question 48

The following two-step process can be used to produce NO₂:
N₂ + O₂ $\rightarrow$ 2NO
O₃ + NO $\rightarrow$ O₂ + NO₂
If 25.0 moles of NO₂ were produced, how many moles of N₂ were used to initiate the sequence of reactions?

A) 25.0 moles
B) 8.00 moles
C) 12.5 moles
D) 16.00 moles

Question 49

A mixture contained 96.4 g of CaCO₃ (molar mass of 100.09) and 68.3 g of MgCO₃ (molar mass of 84.31). How many grams of CO₂ (molar mass of 44.01) will be produced when the mixture is heated?
CaCO₃(g) $\rightarrow$ CaO(s) + CO₂(g)
MgCO₃(g) $\rightarrow$ MgO(s) + CO₂(g)

A) 32.1 g
B) 96.3 g
C) 78.0 g
D) 46.0 g

Question 50

The process for a piece of iron corroding to form rust, Fe₂O₃* H₂O, is given in the two reactions below. How much rust will be formed if 25.0 g of Fe (molar mass = 55.84) completely corrodes to form Fe₂O₃ *H₂O (molar mass = 177.70)?
4 Fe + 12 H⁺ + 3 O₂ $\rightarrow$ 4 Fe³⁺ + 6 H₂O
2 Fe³⁺ + 4 H₂O $\rightarrow$ Fe₂O₃ *H₂O + 6 H⁺

A) 9.94 g
B) 15.9 g
C) 19.9 g
D) 39.8 g

Question 51

Balance the following equations:
-_____HPO₃ + _____C → _____H₂ + _____CO + _____P₄

Question 52

Balance the following equations:
-_____V₂O₅ + _____Ca → _____CaO + _____V

Question 53

Balance the following equations:
-_____BaCl₂ + ________H₂SO₄ → _____BaSO₄ + _____HCl

Question 54

Balance the following equations:
-_____C₂H₆O + _____O₂ → _____CO₂ + _____H₂O

Question 55

Balance the following chemical equation using the simplest whole number ratio of coefficients.
____ I₄O₉ → ____ I₂O₅ + ____ I₂ + ____ O₂

Question 56

Balance the following chemical equation using the simplest whole number ratio of coefficients.
____ C₆H₁₄ + ____ O₂ → ____ H₂O + ____ CO₂

Question 57

Identify the products of and then write a balanced chemical equation for the following reaction.
K₂SO₄(aq) + BaCl₂(aq) → ? + ? (double-replacement reaction)

Question 58

Identify the products of and then write a balanced chemical equation for the following reaction.
NaN₃(s) → ? + ? (decomposition reaction)

Question 59

Verify the Law of Conservation of Mass using the molar masses of the compounds in the balanced equation given below.
Na₂CO₃ + 2 HCl → CO₂ + H₂O + 2 NaCl

Question 60

How many grams of N₂H₄ are needed to produce 6.94 g of H₂O using the reaction:
N₂H₄ + 2H₂O₂ → N₂ + 4H₂O

Question 61

Consider the following reaction:
3 O₂ (g) + 2 CH₄ (g) + 2 NH₃ (g) → 2 HCN (g) + 6 H₂O (l)
How many grams of HCN will be formed upon the complete reaction of 55.8 g O₂ with excess methane and ammonia?

Question 62

How many grams of O₂ (molar mass = 32.00) are produced at the same time that 2.68 moles of KCl are produced using the reaction:
2 KClO₃ → 2 KCl + 3 O₂

Question 63

Consider the reaction:
K₂Cr₂O₇ + 6 KI + 7 H₂SO₄ → Cr₂(SO₄)₃ + 4 K₂SO₄ + 3 I₂ + 7 H₂O
How many grams of KI will be needed to produce 75.0 grams of water?

Question 64

How many grams of H₂O (molar mass = 18.02) can be produced from 20.0 g of H₂S (molar mass = 34.08) and 40.0 g of O₂ (formula mass = 32.00) using the reaction:
2 H₂S + 3 O₂ → 2 SO₂ + 2H₂O

Question 65

The alcohol in "gasohol" burns according to the following equation:
C₂H₅OH (l) + 3 O₂ (g) → 2 CO₂ (g) + 3 H₂O (l)
a) What is the theoretical yield of carbon dioxide when 12.5 g of ethanol, C2H5OH, reacts with 35.0 g of oxygen?
b) What is the percentage yield for this reaction if the actual yield is 20.5 g of CO₂?

Question 66

In a certain experiment 25.0 g of NaCN (molar mass = 49.01) was produced from 40.0 g of N₂ and an excess of other reactants using the reaction
Na₂CO₃ + 4 C + N₂ → 2 NaCN + 3 CO
What is the percent yield of NaCN?

Question 67

Acrylonitrile (C₃H₃N) is the starting material in the production of synthetic fibers (acrylics). Acrylonitrile can be produced from the reaction between propylene (C₃H₆) and nitric oxide (NO).
4 C₃H₆ + 6 NO → 4 C₃H₃N + 6 H₂O + N₂
If 17.66 g of C₃H₃N is experimentally obtained from the reaction of 50.0 g of C₃H₆ and an excess of NO, calculate the theoretical yield and the percent yield for this reaction.

Question 68

Burning of coal to produce electricity leads to the production of sulfuric acid (H₂SO₄), a component of acid rain, in the atmosphere in a three step process shown below.
S + O₂ → SO₂
2 SO₂ + O₂ → 2 SO₃
SO₃ + H₂O → H₂SO₄
If 5.00 x 10⁴ kg of sulfur undergoes complete reaction with excess oxygen and water, what mass of sulfuric acid (in grams) is produced in the atmosphere?