What is the equation for the combustion of propyne?

Propyne is C3H4, and combustion means burning in Oxygen, or O2

So, start with C3H4 + O2 --> ? ?

Combustion results in H2O and CO2

So write as C3H4 + O2 --> H2O + CO2

There are three Carbons on the left, so make the right have three, and since there is O2 on the left, it will always be an even number of O, so try H2O, who has an odd number of O, as 2 (or any even numbers)

Continue doing this until the left and right sides of the equations have the same number of C's, O's, and H's.

Answer: C3H4 + 4O --> 2H2O + 3CO2