Unit 9 Test – Chemistry I

DIRECTIONS: Solve the following problems. Show all of your work and circle your final answer.

1.) What mass (in grams) of hydrogen gas is produced if 20.0 moles of zinc are added to
excess hydrochloric acid according to the following equation?

Zn (s) + 2 HCl (aq) à ZnCl₂ (aq) + H₂ (g)

20.0 moles ? g

1.) Already done! J

2.) 20.0 moles Zn = x moles H₂ 1 ^. x = 20.0 ^. 1

1 1 x = 20.0 moles H₂

3.) 20.0 moles H₂ ^. 2 g/mole = 40.0 grams H₂

2.) What mass (in grams) of 1 – chloropropane (C₃H₇Cl) is produced if 400. grams of propane
(C₃H₈) react with excess chlorine gas according to the following equation?

C₃H₈ + Cl₂ à C₃H₇Cl + HCl

400. g ? g

1.) 400. g C₃H₈ = 9.09 moles C₃H₈
44 g/mole

2.) 9.09 moles C₃H₈ = x moles C₃H₇Cl 1^. x = 9.09 ^. 1

1 1 x = 9.09 moles C₃H₇Cl

3.) 9.09 moles C₃H₇Cl ^. 78.5 g/mole = 714 g C₃H₇Cl

3.) What mass (in grams) of sodium hydroxide is produced if 20.0 grams of sodium metal
reacts with excess water according to the following chemical equation?

2 Na (s) + 2 H₂O (l) à 2 NaOH (aq) + H₂ (g)

20.0 g ? g

1.) 20.0 g Na = 0.870 moles Na

23 g/mole

2.) 0.870 moles Na = x moles NaOH 2 ^. x = 0.870 ^. 2

2 2 2x = 1.74

x = 0.870 moles NaOH

3.) 0.870 moles NaOH ^. 40 g/mole = 34.8 g NaOH

SELECT THE BEST ANSWER AND WRITE IT TO THE LEFT OF THE NUMBER OF THE QUESTION.

4.) For the reaction, 2 H₂ + O₂ à 2 H₂O , how many grams of water are produced from
6.00 moles of hydrogen?

(A) 2.00 g (B) 6.00 g (C) 54.0 g (D) 108 g

1.) already done for you!

2.) 6.00 moles H₂ = x moles H₂O 2 ^. x = 6.00 ^. 2

2 2 2x = 12

x = 6.00 moles H₂O

3.) 6.00 moles H₂O ^. 18 g/mole = 108 g

5.) For the reaction, 3 Fe + 4 H₂O à Fe₃O₄ + 4 H₂ , how many moles of iron oxide are
produced from 5.0 x 10² grams of iron?

(A) 1.0 mole (B) 3.0 moles (C) 9.0 moles (D) 12 moles

1.) 5.0 x 10² g Fe = 8.93 moles Fe

56 g/mole

2.) 8.93 moles Fe = x moles Fe₃O₄ 3 ^. x = 8.93 ^. 1

3 1 3x = 8.93

x =2.98 moles Fe₃O₄

3.) not needed! J

6.) For the reaction, CH₄ + 2 O₂ à CO₂ + 2 H₂O , how many moles of carbon dioxide are
produced from the combustion of 100. grams of methane (CH₄)?

(A) 6.23 moles (B) 10.8 moles (C) 12.5 moles (D) 25 moles

1.) 100. g CH₄ = 6.25 moles CH₄

16 g/mole

2.) 6.25 moles CH₄ = x moles CO₂ 1 ^. x = 6.25 ^. 1

1 1 x = 6.25 moles CO₂

3.) not needed! J

7.) For the reaction, Cl₂ + 2 KBr à 2 KCl + Br₂ , how many moles of potassium chloride
are produced from 119 grams of potassium bromide?

(A) 0.119 moles (B) 0.236 moles (C) 0.581 moles (D) 1.00 mole

1.) 119 g KBr = 1.00 mole KBr

119 g/mole

2.) 1.00 mole KBr = x moles KCl 2 ^. x = 1.00 ^. 2

2 2 2x = 2.00

x = 1.00 mole KCl

3.) not needed

8.) For the reaction, 2 H₂ + O₂ à 2 H₂O , how many moles of water can be produced from
6.0 moles of oxygen?

(A) 2.0 moles (B) 6.0 moles (C) 12 moles (D) 18 moles

9.) In the reaction, N₂ + 3 H₂ à 2 NH₃ , what is the mole ratio of nitrogen (N₂) to
ammonia (NH₃)?

(A) 1 : 1 (B) 1 : 2 (C) 1 : 3 (D) 2 : 3

10.) In the reaction, 2 Al₂O₃ à 4 Al + 3 O₂ , what is the mole ratio of aluminum to
oxygen?

(A) 10 : 6 (B) 3 : 4 (C) 2 : 3 (D) 4 : 3

11.) In the reaction, 2 H₂ + O₂ à 2 H₂O , what is the mole ratio of oxygen to water?

(A) 1 : 2 (B) 2 : 1 (C) 8 : 1 (D) 1 : 4

12.) In the reaction, Ca + Cl₂ à CaCl₂ , what is the mole ratio of chlorine to calcium
chloride?

(A) 2 : 3 (B) 2 : 1 (C) 1 : 2 (D) 1 : 1

13.) In the chemical reaction, w A + x B à y C + z D , a comparison of the number of
moles of A to the number of moles of C would be a(n)

(A) mass ratio (B) mole ratio (C) electron ratio (D) energy proportion

14.) The Haber process for producing ammonia commercially is represented by the equation,
N₂ (g) + 3 H₂ (g) à 2 NH₃ (g). To completely convert 9.0 moles of hydrogen gas to
ammonia gas, how many moles of nitrogen gas are required?

(A) 1.0 moles (B) 2.0 moles (C) 3.0 moles (D) 6.0 moles

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