Name_______________________
Chem 111 Quiz
Chapt 5
Winter, 2004
Potentially useful information: Show all work, including any unit conversions for full
credit. Use correct number of sig figs.
1. Give oxidation numbers for each and every atom in all of the following molecules:
HNO3
H +1, O -2, N +5
C2H2
H +1, C -1
MnO4-
O -2, Mn +7
2. Balance the following reactions.

1 Ag2S (s) +
2 HCl (aq)
1 BaCl2(aq) +
1 Na2CO3(aq) 
6 CO2 (g) +
6 H2O (l)
2 HCl (aq) +
1 CaCO3 (s) 

2 AgCl (s) +
1 H2S (g)
1 BaCO3 (s) +
2 NaCl (aq)
1 C6H12O6 (s) +
6 O2 (g)
1 CaCl2 (aq)
+1 CO2 (g) + 1 H2O (l)
3. In the following redox reaction:
CuSO4 (aq) + Zn (s) 
Cu (s) +
reactant ox. #: Cu +2, S +6, O -2, Zn 0
ZnSO4 (aq)
product ox. #: Cu 0, Zn +2, S +6, O -2
What is being oxidized? What is reduced? What is the oxidizing agent? Explain
your answers.
copper goes from +2 to 0 → it is reduced, therefore it is oxidizing agent
zinc goes from 0 to +2 → it is oxidized, therefore it is reducing agent
4. Examine the following reaction (the burning of an acetylene torch).
2 C2H2 (g) +
5 O2 (g) 
4 CO2 (g) +
2 H2O (g)
If one burns 65.0 g of acetylene (C2H2) in the presence of 192 g of diatomic oxygen,
which reactant is in excess?
g acetylene → moles acetylene → moles oxygen →g oxygen
65.0 g x 1 mole/24.04 g x 5 oxygen/2 acetylene x 32.00 g/ mole = 216 g oxygen
oxygen is limiting reagent since we only have 192 g
so acetylene is in excess
Which reactant is the limiting reagent?
oxygen is limiting reagent
How many moles of CO2 are produced (theoretical yield)?
192 g oxygen x 1 mole/32.00g x 4 CO2/ 5 O2 x 44.01 g/mole = 211 g CO2
How many grams of H2O are produced (theoretical yield)?
192 g oxygen x 1 mole/32.00g x 2 H2O/ 5 O2 x 18.02 g/mole = 43.2 g H2O