The reaction is a single replacement reaction, as the aluminum is REPLACING the copper attached to the sulfate. the exponents on the equation, in order, would be 2, 3, 1, 3. The reaction represents a chemical change because a new compound is being formed; if the original compound was simply changing state ( from liquid to gas, etc), then the change would be physical.
The last question requires some stoichiometry. My work is attached.