What is the word equation for a general combustion reaction?
Hydrocarbons (which are only hydrogen and carbon) require oxygen to combust, and they form water and carbon dioxide. So a general formula might look something like this:CnHm + (m/4 + n)O2 → (m/2)H2O + nCO2where n is the number of carbons in the hydrocarbon and m is the number of hydrogens. In hydrocarbon equations, it's very possible to have a fraction for the oxygen. Combustion reactions are one of few reactions where it's acceptable to do this. However, some teachers may still ask you to get rid of the fraction. To do this, multiply each compound's coefficient by two (or whatever the denominator is in oxygen's coefficient, but it will rarely be anything but two because the number of hydrogens, m, will almost always be even).