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How do we represent the heat evolved in exothermic reactions?

Answer 1

Henry Antrim

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

We are aware that certain chemical processes, like the burning of hydrocarbons, release energy:

#CH_4(g) + 2O_2(g) rarr CO_2(g) +2H_2O(l) + "energy"#

..or, more frequently.....

#CH_4(g) + 2O_2(g) rarr CO_2(g) +2H_2O(l) + Delta#

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

By convention, this energy is reported as a NEGATIVE value. 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).

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Answer 2

Jeremiah Adams

Heat is written and included in product side to emphasize that the reaction is exothermic (release of heat).

Remember that heat absorption and release are simply measurable signs that a chemical reaction has occurred. Some people argue that heat is a product of an exothermic reaction, but this only serves to highlight the fact that heat is being released in the reaction.

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Answer 3

Jose Ayala

Negative sign indicates heat evolved in exothermic reactions.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.