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
