4) Propane burns in oxygen to form water and carbon dioxide according to the following balanced equation. Assuming all heat comes from this reaction, a) what mass of propane must be burned to provide 1.3 x 10% J? b) What mass would be needed if the heat transfer process was only 60% efficient? C3HS ()+5 O2 (8) 3 CO2 (8) +4 H2O () (8) AH = -2,221 kJ %3D