Answer:
1400KJ/mol⁻¹
Step-by-step explanation:
Amount of heat required can be found by:
Q = m × c × ΔT
Where m is the mass, c is the specific heat capacity (4.2KJ for water) and ΔT is the change in temperature.
Q = 24 × 4.2 × (23 - 9)
= 24 × 4.2 × 14
= 1411.2KJ/mol⁻¹
= 1400KJ/mol⁻¹ (to 2 significant figures)