Chapter 3

1) 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

2) 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 + H_2O → Ca(OH)₂

• E) 2CH₄ + 4O₂ → 2CO₂ + 4H₂O

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

• A) oxygen

• B) nitrogen

• C) carbon dioxide

• D) water

• E) argon

4) When a hydrocarbon burns in air, a component produced is?

• A) oxygen

• B) nitrogen

• C) carbon

• D) water

• E) argon

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

• A) NH₄Cl → NH₃ + HCl

• B) 2Mg + O₂ → 2MgO

• C) 2N₂ + 3 H₂ → 2NH₃

• D) 2CH₄ + 4O₂ → 2CO₂ + 4H₂O

• E) Cd(NO₃)O₂ + Na₂S → CdS + 2NaNO₃

6) Which one of the following substances is the product of this combination reaction?

Al (s) + I₂ (s) → __________

• A) AlI₂

• B) AlI

• C) AlI₃

• D) Al_2I₃

• E) Al₃I₂

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

• A) They are inflated as a result of a decomposition reactio

• 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.

8) 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

9) 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

10) 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