C3H8 ( g ) + 5 O2 ( g ) = 3 CO2 (g ) + 4 H2O ( g ) , This is a complete combustion of Propane gas ( C3H8 ) , converting all 3 C from it to 3 MOLES OF CO2 GAS , and the overall reaction is in balanced state since associated 8 atoms of H of propane gas is paricipating with O2 gas to form 4 moles of WATER VAPOR , proving THE PRODUCT WOULD BE : Carbon dioxide and water only