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 Avogadros 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):

 

__ ______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 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 3 FeCl2

 

 

 

2. 4 Al + 3 O2 2 Al2O3

 

 

 

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

 

 

 

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

 

 

 

5. 3 IBr + 4 NH3 NI3 + 3 NH4Br

 

 

 

6. Cl2 + HOH HCl + HClO

 

 

 

7. 2 AgNO3 2 AgNO2 + O2

 

 

 

8. 12 HClO4 + P4O10 4 H3PO4 + 6 Cl2O7

 

 

 

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

 

 

 

10. Sodium hydroxide + Hydrochloric acid sodium chloride + water

NaOH + HCl NaCl + HOH