Balance the following equations;
a) CH4(g) + O2(g) --heat--> CO2(g)
+ H2O(g)
Answer
This equation appears to be a little more complicated that
the formation equations we were discussing. But if maintain
control we'll see these are not that difficult. It is all in the
approach.
To balance combustion reactions always balance the element
oxygen, O2, last. If we do that we need to balance
carbon and hydrogen first, we'll do that beginning with carbon.
CH4(g) + O2(g)
--heat--> CO2(g) + H2O(g)
There is one carbon atom on both sides so that
was easy!
Now hydrogen...let's see four hydrogen atoms on
the left (CH4) and only two on the right (H2O).
So I'll need to change the coefficient before H2O from
'1' to '2' and that will balance the hydrogen atoms.
CH4(g) + O2(g)
--heat--> CO2(g) + 2H2O(g)
Now we'll balance the oxygen atoms. There are
two oxygen atoms (O2) on the left and four oxygen
atoms on the right (CO2 + 2H2O). So I'll
need to change the coefficient from a '1' to a '2' in front of O2.
CH4(g) + 2O2(g)
--heat--> CO2(g) + 2H2O(g)
Now the equation is balanced.