Answer:
70 g
Explanation:
ice at zero degree will melt and cool down water from 20 degree to 5 degree
heat gained by ice in melting
= mass x heat of fusion
= m x 333.7 x 10³ J
Heat gained by water at zero to water at 5 degree
= mass x specific heat x rise in temperature
= m x 4.18 x 10³ x 5
Total heat gained
= m x 333.7 x 10³ +m x 4.18 x 10³ x 5
= 354.6 x 10³ m J
mass of water = .4 x 1
= .4 kg
heat lost by hot water at 20 degree to 5 degree
= .4 x 4.18 x 10³ x ( 20-5 )
=25.08 X 10³ J
Heat lost = heat gained
354.6 x 10³ m = 25.08 X 10³
m = 25.08 / 354.6
= .070 kg
70 g
b )
Let the water required be m kg
heat gained by water
= m x 4.18 x 10³ x 15
m x 4.18 x 10³ x 15 = 25.08 X 10³
m = 25.08 / (4.18 x 15)
= .4 kg
= 400 gm
=