Question

How much steam at 100^oC must be passed into 120 g of water at 20^oC to raise the temperature to 40^oC? 

Answer 1

Let the mass of steam be m.
Heat lost by (steam at 100°C to oondense into water at 100°C + 100°C water to oonvert into 40°C wa:er =Heat gained by water to raise the temperature to 40°C

m x 2268 + m x 4.2 x (100 - 40) = 120 x 4.2 x ( 40 - 20)
m (2268 + 252) = 10080
m = 4g