How do we represent the heat evolved in exothermic reactions?

Mar 14, 2016

You might have to restate your question. I am unsure as to what you are asking.

Explanation:

We know that there are chemical reactions that release energy, for instance the combustion of hydrocarbons:

$C {H}_{4} \left(g\right) + 2 {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right) + 2 {H}_{2} O \left(l\right) + \text{energy}$

..or, very commonly.....

$C {H}_{4} \left(g\right) + 2 {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right) + 2 {H}_{2} O \left(l\right) + \Delta$

...where the $\Delta$ symbol represents heat or energy. And this can certainly be quantitatively measured.

Now the energy that results from the formation of carbon dioxide and water can be measured (and of course be utilized to warm our baths and cook our breakfasts). By convention, this energy is reported as a NEGATIVE value.

Mar 14, 2016