Write the balanced equation for each of the following changes and identify whether heat is a product or needed to start the reaction (do not include 'heat' in your balanced equation, simply identify whether it is a product or reactant):
(a) the sublimation of dry ice [conversion of CO2(s) directly to CO2(g)] Heat is a product and is given off by the reaction. Heat is a reactant and is needed to start the reaction.
(b) the reaction of 1 mol of sulfur dioxide with oxygen. Heat is a reactant and is needed to start the reaction. Heat is a product and is given off by the reaction.