# Calculation of heat of hydration

1. Feb 17, 2007

### nathaniell

How do I calcualte the heat of hydration of of copper(II)sulphate knowing that when I dissolve anhydrous copper(II)sulphate temperature changes by 2K and when I dissolve copper(II)sulphate pentahydrate in water temperature decreases by 1K.

We are told to assume that 1cm cubed of water is equivalent to 1gram.

The mass of copper(II)sulphate pentahydrate used is 12.5g and the mass of anhydrous copper(II)sulphate is 8.00g

I need to calculate the heat of hydration from the given data? and I can't do it... so please help people.

2. Feb 17, 2007

### Staff: Mentor

This might give some insight

http://www.rit.edu/~axlsch/classes/schp445/Hydrate lab.pdf

Are all the data provided. I would expect mass of the water is needed.

The heat given off by hydration raises the temperature of the solution. (mass of the solution * specific heat * temperature change) = heat of hydration (kJ/mol) * no. of moles of salt reacting

One reaction is exothermic and the other is endothermic