Hey i need help with this 1 question. I've looked through my AP Chem book but it does not really help much with this type of problem:

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Juan performed a calorimetry experiment to determine ∆H for the following reaction: KOH (s) --> K(aq) + OH(aq)

His calorimeter contained 64.0 g of water at an initial temperature of 20.7°C. When he added 1.65 g of KOH (s) to the calorimeter, the temperature rose to 26.9°C. What value of ∆H can Juan obtain fromhis data?
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I really dont know where to start and the only formula i know for this type of problem is q=ms∆t but that does not really help finding ∆H. The only ∆H problem i have worked with are ones concerning Hess's Law.

Thanks in advanced.