Question

1000w heater is used in the determination of specific latent heat of vaporization of water and it took 4 minutes for 500g of water to be changed to steam. Calculate the latent heat of vaporization of water.

Answer 1

4 min * 60 = 240 seconds
1000 W = 1000 Joule / second
so we put 240,000 Joules into 0.5 kg of the water
so we needed 480,000 Joules per kg
or 480 Joules/gram

Answer 2

by the way that is nothing like the usual accepted value.