10.00 g of Compound X with molecular formula CzHg are burned in a constant-pressure calorimeter containing 10.00 kg of water at 25 C. The temperature of the water is observed to rise by 10.42 C. (You may assume all the heat released by the reaction is absorbed by the water, and none by the calorimeter itself.) Calculate the standard heat of formation of Compound X at 25 C. Be sure your answer has a unit symbol, if necessary, and round it to 2 significant digits