How many kilowatt-hours are produced when the burning of 0.562 g of graphite produces 18 kJ of heat?

Question

is it 5 X 10 ^ -6, -5, -4, -3, 3

Answer 1

This is an excise with math and physics units:
18 kJ = 18000 J
= 18000 watt*s
=300 watt*min
= 5 watt-hours
= 5x10^-3 kilowatt-hours.