2kg of ice at `-20^@C` is mixed with 5kg of water at `20^@C` in an insulating vessel having a negligible heat capacity. Calculate the final mass of water remaining in the container. It is given that the specific heats of water & ice are `1kcal//kg//^@C` and `0.5`
`kcal//kg//^@C` while the latent heat of fusion of ice is `80kcal//kg`

Answer

6

Explanation

Energy with 5 kg of `H_(2)O` of 20°C to become ice at 0°C `E_(1)=5000xx1xx20=100000cal`
Energy to raise the temperature of 2 kg ice from –20°C to 0°C is `E_(2)^(@)20000xx0.5xx20=20000cal`
`(E_(1)-E_(2))=80,000cal` is available to met ice at 0°C. So only 1000 g or 1 g of ice would have melt.
So amount of water available is