Acetylene gas (ethyne hc=ch) burns in an oxyacetylene torch to produce carbon dioxide and water vapor, and the heat needed to weld metals. the heat of reaction for the combustion of acetylene is -1259 kjmol. (a) calculate the c=c bond energy, and compare your value with that in the table. (b) when 395.0 g of acetylene burns, how many kilojoules of heat are given off? (c) how many grams of co2 form? (d) how many liters of o2 at 298 k and 15.6 atm are consumed?