A 2.00 g sample of solid RbClO4 (M = 184.92) is added to 100.0 g water, both initially at 23.00 °C, — Thermochemistry Chemistry Question

A 2.00 g sample of solid RbClO₄ (M = 184.92) is added to 100.0 g water, both initially at 23.00 °C, in a well-insulated container. The final temperature of the solution is 21.56 °C. What is ∆H°solution of RbClO4? (Assume that the specific heat capacity of the solution is the same as that of pure water and neglect the heat capacity of the insulated container.)