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