When sulfuric acid is added to calcium nitrate, nitric acid and calcium sulphate are produced. This is illustrated by the equation Ca(NO3)2(aq) + H2SO4(aq) = CaSO4(s) + 2 HNO3(aq).
In the above chemical reaction, a molecule of calcium nitrate combines with a molecule of sulfuric acid to produce a molecule of calcium sulphate plus 2 of nitric acid. The chemical reaction is an exergonic reaction because it produces a lot of energy in the form of heat. This usually happens when sulfuric acid is added to water or to solutions containing water, as in this case. The reaction is also called a spontaneous chemical reaction, because it occurs on its own and without any energy input from the surroundings.