The combustion reaction of propane (C3H8), a gas used for heating, is shown in the following thermochemical equation: C3H8+ 502 -->3CO2+4H2O deltaH = -2221kJ Calculate how much propane gas must be burned to obtain one amount of heat of 8 x 107 J, if the process has a yield of 60%

Answer 1

If the yield were 100%, you would need this.
44 g C3H8 (1 mol) will produce 2221 kJ of heat, so you will need
44 g x (8 x 10^4 kJ/2221 kJ) = 1585 g to produce 8 x 10^7 J. For a reaction that is only 60% efficient, you will need
% yield = (actual yield/theoretical yield)*100
60 = (1585/X)*100 = ? where X = amount of C3H8 that must be used initially to produce 8E4 kJ @ 60% efficiency.