9/20 Concept Test Questions

1. What is the oxidation number of phosphorus in the phosphate ion?
A) -5
B) -3
C) 0
D) +3
E) +5

2. Which of these is a redox reaction?
A) 2NaOH + H2SO4 -> Na2SO4 + 2H2O
B) 2AgNO3 + Cu -> Cu(NO3)2 + 2Ag
C) Pb(NO3)2 + 2KI -> PbI2 + 2KNO3
D) CaCO3 + 2HCl -> CaCl2 + CO2 + H2O

3. A 5-gallon steel can, containing a small amount of water, is heated. The can is sealed and removed from the heat. Predict what will happen as the can cools.
A) Nothing. Steel is very strong.
B) The can distorts and expands.
C) The can distorts and collapses.