Answer:
a) 4869 kJ will be released
b) 43.86 g of octane
Explanation:
The heat of combustion is the amount of heat released when 1 mol of a substance reacts with enough oxygen .
Since the heat of combustion is per mol of combustible substance what we are required to do in this problem is calculate number moles in the reactions although in a different manner.
a) MW C3H6O = 158 g/mol
mol C3H6O = 158 g x 1 mol/58.08 g = 2.72
-1790 kJ/ mol x 2.72 mol = 4869 kJ
b) Here we are asked the mass of octane to produce 1950 kJ of heat knowing that per mol of octane we get 5074.1 kJ, then
1 mol / 5074.1 kJ x 1950 kJ = 0.384 mol
mass C8H18 = 0.384 mol x 114.23 g/mol = 43.86 g
