CHM 2045C Module Five Sample Exam Answers

Module Five-Part E   Basic Stoichiometry Definitions      4 points

Write the definitions to the following words:

 

Mole  is the amount of substance that contains Avogadro’s number of particles, that is 6.02 x 10 23 particles or entities .

(A chemist dozen: 6.023 x 10 23 objects, where the objects are atoms, ions, molecules, electrons or other particles)

 

 

Reactants is the substance that undergoes a chemical change

 

 

 

Products the resulting substance from a chemical change

 

 

 

Catalyst  is a substance that speeds up a chemical reaction without being consumed or permanently altered

 

 

 

Precipitate is an insoluble substance  produced by a chemical reaction in an aqueous solution

 

 

Fill in the following with the symbols used in chemical equations which has the stated translation or meaning(s):

 

__  à  ______1.  Produces, yields

 

____ (s) _____ or ___ ______ 2. Solid substance or precipitate forms

 

 

____ (g) _____ or _________3.  Gaseous substance formed

 

 

__  (aq) _______4.  Water or aqueous solution

 

 

Show the symbol for heat:__   _______

 

How would you show a catalyst in a chemical reaction where A plus B forms products D and E, but is catalyzed by substance C:

                     C

       A  +  B  à  D  +  E

 

Module Five-Part F Balancing Chemical Equations (Section 4.2)     5 points

Balance the following chemical equations (write the chemical formulas in #10 then balance):

Suggested Additional Homework: Kotz6e p166 #1-6

 

1.          Fe     +     2 FeCl3       à      3 FeCl2

 

 

 

2.         4 Al        +      3 O2         à      2 Al2O3

 

 

 

3.          Na2CO3   +    4 C       +   N2    à    2 NaCN       +       3  CO

 

 

 

4.         4  FeS        +    7 O2    à     2  Fe2O3    +      4  SO2

 

 

 

5.        3  IBr      +     4  NH3        à        NI3          +     3  NH4Br

 

 

 

6.           Cl2       +      HOH       à       HCl         +     HClO

 

 

 

7.         2  AgNO3    à     2  AgNO2         +     O2

 

 

 

8.          12  HClO4      +     P4O10    à    4  H3PO4     +    6  Cl2O7

 

 

 

9.         2   HCl         +        Mg(OH)2   à     MgCl2      +    2  HOH

 

 

 

10.  Sodium hydroxide +   Hydrochloric acid  à   sodium chloride   +   water

               NaOH               +              HCl              à           NaCl                +   HOH