Question

How do you write a balanced equation for the complete combustion of `C_3H_6O`?

Answer 1

Add coefficients in front of each species so there is the same number of atoms of each element on both sides of the equation. Never change subscripts.

Explanation:

Complete combustion of an organic substance requires oxygen and produces carbon dioxide and water.

Unbalanced Equation

`"C"_3"H"_6"O" + "O"_2` `rarr` `"CO"_2" + H"_2"O"`

Balanced Equation

`"C"_3"H"_6"O" + "4O"_2` `rarr` `"3CO"_2" + 3H"_2"O"`

Notice that there are 3 carbon atoms on both sides, 6 hydrogen atoms on both sides, and 9 oxygen atoms on both sides.

Also notice that no chemical formula was changed (no change in subscripts.