Chemistry urgent help?

When water reacts with lithium, it produces lithium hydroxide and hydrogen gas. The ΔH of this reaction is -708 kJ per mole of lithium. If 50.0 mL of water at 19.2oC reacts with 79.7 mg of lithium, what is the final temperature (in oC)? The heat capacity of the cup containing the water (which is also originally at 19.2oC) is 74.3 J/oC. Since only a small amount of water reacts, ume that the specific heat and amount of liquid remains unchanged.