Question

I have a solid dissolved in water, both the same temp, and when it's put in the temperature drops. I have the heat capacity it of the solution, and need to the molar heat of the solution of the solid that was dissolved.

Right now I've got:

Mass of water x heat capacity x change in temp.

Then I converted the amount in grams of solid to moles, and divided the heat I got by it.

Am I doing this right? Should I be adding the mass of the solute/solid to the mass of the water? Or just using the mass of the water like I am? I keep finding pages that do it different ways.

Answer 1

It appears tp me ou have done it right. You do not add the mass of the solid to the water. You solved for q and got delta H/mol by dividing by the mols of the solid. The only thing left, I think, is to convert J/mol to kJ/mol since that is the usual way of calculating it but if your problem doesn't actually say kJ/mol you may not need to do it.

Answer 2

Yea, I do have to go to kJ/mol. Just wanted to focus on that step for the question here. Thanks.