How are ionic bonds and covalent bonds different

In order to calculate the amount of heat transferred you must know the __ and specific heat of the material, as well as the change in temperature. a. volume b. density c. mass d. enthalpy

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.