Determine the amount of heat (in kJ) required to vaporize 1.55 kg of water at its boiling point. For water, Δ_Hvap = 40.7 kJ/mol (at 100 °C).

a) 3.50 * 10³ kJ 

b) 1.14 * 10⁶ kJ

c) 2.11 kJ 

d) 686 kJ