[lou_skywalker]

Acetylene gas (ethyne; HC≡CH) burns in an oxyacetylene torch to produce carbon dioxide and water vapor. The heat of reaction for the combustion of acetylene is -1259 kJ/mol.

(a) Calculate the C≡C bond energy.
(b) When 716.0 g of acetylene burns, how many kilojoules of heat are given off?

So I got the equation 2(C2H2)+5(O2) :rarrow:4(CO2)+2(H2O)...but no idea what to do with it :S