Compare and comment on your answers to questions 32 and 33.

Data from question no.32

A car’s fuel tank holds 40 kg of petrol.

■■ 1 kg of petrol releases 5 × 10⁷ J of energy when it burns.

■■ Only 40% of the energy released when the petrol burns is converted into useful work.

■■ 1 × 10⁶ J of work is needed to drive the car 1 km.

Data from question no.33

A fuel cell vehicle with a similar volume fuel tank can store 400 g of hydrogen at high pressure.

■■ 2 g of hydrogen release 286 000 J of energy when used in the vehicle’s fuel cells.

■■ 60% of the energy released from the fuel cell is converted into useful work.

■■ 1 × 10⁶ J of work is needed to drive the car 1 km.