10.1 g CaO is dropped into a styrofoam coffee cup containing 157 g H2O at 18.0°C. If the following reaction occurs, then what temperature will the water reach, assuming that the cup is a perfect insulator and that the cup absorbs only a negligible amount of heat? (the specific heat of water = 4.18 J/g•°C) CaO(s) + H2O(l) → Ca(OH)2(s) ΔH°rxn = -64.8 kJ/mol