Question

To treat a burn on your hand, you decide to place an ice cube on the burned skin. The mass of the ice cube is 17.1 g, and its initial temperature is -11.4 °C. The water resulting from the melted ice reaches the temperature of your skin, 28.1 °C. How much heat is absorbed by the ice cube and resulting water? Assume that all the water remains in your hand. Answer in J

Answer 1

The water loses sensible heat from -11.4 deg.c to 0 deg.c, then looses latetn heat at 0 deg.c and then from 0 deg.c to 28.1 deg.c. The total heat is sum of all these three heat energies

Specif heat of ice : 2.108 j/ g.k specific heat of liquid water : 4.187 j/g,k and latent heat of fusion of ice= 333.55 j/g

1. Sensible heat of ice = mass* specific heat of ice * temperature difference= 17.1*2.108*{0-(-11.4} =17.1*2.108*11.4 joules=410.9 joules

2. Latent heat of fusion for 17.1 gms = mass* (latent heat of vaporization/ gm)17.1*333.55 j/g=5703.77 joues

3.Sensible heat of liquid ice = 17.1*4.18*(28.1-0)= 2008.532 joules

Total heat absorbed by ice= 1+2+3= 410.9+5703.77+ 2008.532 joules = 8123.17 joules