# Is there more than one equation for Delta T(reaction)?

So, I have to find the $\Delta T_{\mathrm{reaction}}$ of a solution for my lab report. Earlier in the lab, it gave the equation as

$\Delta T_{\mathrm{reaction}}=T_{\mathrm{mixture}}+\frac{1}{2}(T_{\mathrm{substance~1}}+T_{\mathrm{substance~2}})$

and all temperatures were at the exact time of mixing found from a linear equation of temperature points on a graph. Now, I have another mixture which is water and a substance and I am supposed to find the $\Delta T_{\mathrm{reaction}}$.

Here's the thing, we don't have the temperature of the substance, only the temp of the water and the solution it made, so how could I go about doing it? I thought about using room temperature since it was a solid substance but it doesn't say anything about that.

The substance is solid $\ce{NaOH}$.

• Please avoid Latex in titles due to searching issues. – bon May 3 '15 at 17:55
• The solid likely was at room temperature, but it also probably had lower mass and almost certainly had lower heat capacity than the solution to which it was added. I suspect that the equation you gave is for mixing two dilute solutions of equal volume. If I'm not mistaken it should be Tmixture - 1/2... rather than + 1/2. – Jason Patterson Jun 3 '15 at 6:38