Question

A 0.50 g sample of vegetable oil gives out 19.9 kJ of heat when burned. What is the caloric value of the oil in kcal/g?

Answer 1

Answer is 9.51 kCal/g

Explanation;

1 kJ = 1000 J

1 J = 0.239 Cal

Hence,

19.9 kJ = 19900 J

19900 J = (0.239 Cal / 1 J) x 19900 J

= 4756.1 Cal

1000 Cal = 1 kCal

Hence, 4756.1 Cal = 4.7561 kCal

Those calories are in 0.50 g of vegetable oil.

Hence, to find out the caloric value of the oil in kCal/g, we have to divide amount of Kcal by mass of the oil.

Then,

caloric value of the oil = heat burned / mass

= 4.7561 kCal / 0.50 g

= 9.5122 kCal/g

= 9.51 kCal/g