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