energy of combustion of biodiesel?

Question

Calculate the energy of combustion per gram of Bio Diesel (kJ/g) if 29.0 mL of water is placed in the test tube and the temperature changes from 22.9 ºC to 41.5 ºC. The initial mass of the spirit burner is 190.20 g and the final mass is 190.09 g. State your answer with correct significant digits.

My final answer is 20.5 kJ/g assuming the water has C = 4.19 J/g

Answer 1

the heat given off (delta H) = specific heat of water x weight of water x temperature change

delta H = 4.19j/gC x 29g x 18.6C = 2,260J

only 0.11g if biodiesel was needed.

Hence 1g biodiesel would produce 2,260J/.11g = 20500J (rounded) which would - 20.5kj/g

So.... you are correct!