[Greg]

Can someone explain how to do this calorimetry problem?

A double displacement reaction took place in a coffee cup calorimeter that had a heat capacity of 76.4 J/degreeC. One reagent was 1000.00mL of .990M Pb(NO3)2. The other reagent was 1117.38mL of KI with an unknown molarity. Both solutions have a density of 1.030g/mL. Both solutions started at 21.3 degreeC. After the precipitation took place the temperature rose to 23.4 degreeC. Assume the specific heat of each reagent is 4.184 J/g×degreeC. If deltaH naught = -23.47kJ/mol of ppt, what is the molarity of the KI solution?

I can't understand how to do this problem for the life of me. I've tried lots of different things but I couldn't get the answer they gave. The answer is 1.47M KI.

Thanks in advance to anyone that helps.

[Borek]

Show what you have tried.