Volume of water = 5 L
Because density of water is 1000 g/L,the mass of water is
m = (5 L)*( 1000 g/L) = 5000 g
The latent heat of vaporization of water is 2257 J/g
Therefore the heat required is
Q = (5000 g)*(2257 J/g)
= 11.285 x 10⁶ J
= 11.85 MJ
Answer: 11.85 MJ