You have the following equation written above:
C4H8 + 6O2 --spark--> 4CO2 + heat
But this is not a balanced chemical equation. There is no hydrogen on the product side and there must be to balance out the hydrogen on the reactant side. C4H8 is n-butene (where "n" symbolizes the location of the carbon-carbon double bond) and this is an equation for the combustion of n-butene. The products are CO2 and H2O. The hydrogen in the water balances out the hydrogens on the right hand side. The complete balanced equation is as follows:
C4H8 + 6O2 ---spark---> 4CO2 + 4H2O + heat
This is the equation for the complete combustion of n-butene. Complete combustion produces only CO2, H2O, and heat as the products. Incomplete combustion produces some CO as a byproduct.
Well this kind of reaction is combustion.
C4H8 + 6O2 --spark--> 4CO2 + 4 H2O + heat .