[Kaitosan]

You mix 132mL of 0.548 M CsOH with 216.0mL of 0.3349 M HF in a coffee cup calorimeter, and the temperature of both solutions rises from 19.90°C before mixing, to 24.40°C after the reaction.
CsOH (aq) + HF (aq)  -->  CsF (aq) + H2O (l)
What is the enthalpy of reaction per mole of CsOH? Assume the densities of the solutions are all 1.00 g/mL and the specific heats of the solutions are 4.18 J/(g·K).



The correct answer is 90.5 kj/mole but I just don't know how to solve the problem. Any help is much appreciated!!!!

[sjb]

How many moles of reactants participated in the reaction you're describing?

[Kaitosan]

Each element stands for one mole since the coefficient is 1 mole..

[ImNotQ...]

Bleh...A lot.
First use the molarity formula: M=moles/liter to find moles of CsOH(.0723).
Then add the two volumes together; why? Because the densities are 1, divide 1 by the volumes to get mass-which you plug into q=mc(delta)t.
Add the volumes, divide by one, and you better get 348 g.
Multiply by the specific heat and temp change to get the enthalpy change of the whole thing. What for? So you can divide that by the moles of CsOH you found to get to 90537.759 J(90.5KJ).
GL memorizing that for the test =D