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

 

 

Back to the Unit 9 Old Test Page

Back to the Unit 9 Page

Back to the Main Page