Acopper penny has a mass of 2.6 g assuming it is pure copper, how much of this mass is contributed by a) the neutrons in the copper nuclei b) the electrons

The equation below shows a chemical reaction. a + b + heat —> c + d according to the law of conservation of energy, which statement is true? a. the reactants absorb heat because they have less energy than the products. b. the products release heat because they have more energy than the reactants. c. the reactants generate heat because they have more energy than the products. d. the products require heat to form because they have less energy than the reactants.