27.0 mL of 1.00 M HClO4 are mixed with 27.0 mL of 1.00 M LiOH in a coffee-cup calorimeter. The thermogram for the reaction is depicted below. The calorimeter constant is 28.1 J/ Celcius. Both solutions were initially at 21.31 Celcius. Calculate Delta Hrxn for the reaction.