How much energy is required to vaporize 0.5kg of water?

Vaporization Equation = > Q = m·ΔHv

m = 0.5Kg water = 500g water

ΔHv = Heat of vaporization = 540 calories/gram

∴Q = 500g x 540cal/g = 270,000 calories x 4.184 joules/cal = 1,129,680 joules = 1130 Kilojoules (3 sig. figs.)