Question #df1ec

1 Answer
Dwight
Mar 5, 2017

A coefficient tells you the relative amount (in moles or in molecules) of that chemical used or produced in the reaction.

Explanation:

Here is an example:

CH_4 + 2 O_2 rarr CO_2 + 2H_2O

In this equation, the "2" in front of O_2 tells us that we will need twice as much oxygen gas as methane (the CH_4 molecule) to have this reaction work as the equation states. If we provide more, it will be left over, and not react. If we provide less, the reaction will not be able to use all the methane.

By the way, if there appears to be no coefficient, you assume that a "1" is there.

Then, on the right side of the arrow (the products) we see that one molecule of CO_2 forms at the same time that two molecules of water are produced.

This coefficients can have units that are either "molecules" or "moles" (if you are familiar with this unit). So we can read the equation as either

"One molecule of CH_4 plus two molecules of O_2 produce one molecule of CO_2 plus two molecules of H_2O"

or

"One mole of CH_4 plus two moles of O_2 produce one mole of CO_2 plus two moles of H_2O"

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