[ankara55t]

Say I have some experimental data from an exothermic reaction. It is change in temperature information. How do I convert this info into a kJ reading? Specifically, for the dissociation of NaOH into Na+ and OH- ions, how can I get a delta H, in kJ/mol for this if all I know is that to get this dissocation resulted in a change in temperature of 6.8 degrees celsius.

[Unknown008]

In such reactions, you have to know the mass of NaOH you're using and the amount of water in which it is dissolved.

You'll have the energy involved by the raise in temperature of the water and you'll have the delta H of reaction by the amount of NaOH dissolved.

To find the energy you'll use:


Q is the amount of energy in kJ,
m is the mass of the water (1 cm^3 = 1 g)
c is the specific heat capacity of water, it's a constant (c of water = 4.2 J/(gK))
Delta theta is the change in temperature.

Then, to find delta H, you need to firstly find the number of moles of reactants. Such amount of reactants give off the amount of energy you got beforehand. Find the amount of energy that would be released if you have 1 mol of reactant.

I hope it helped! :)

[ankara55t]

Thank you especially on New Year's Day-good to think when most operations are closed

[Unknown008]

You're welcome! :)