Suppose you take a 50gram ice cube from the freezer at an initial temperature of -20°c. how much energy would it take to completely vaporize the ice cube? (hint: think of this process as four separate steps and calculate the energy needed for each one.)

The amount of energy required is

Explanation:

The energy required to convert the ice to steam is the sum of:

1) Energy required to raise the temperature of the ice from -20 to 0 degree Celsius.

2) Latent heat required to convert the ice into water.

3) Energy required to raise the temperature of water from 0 degrees to 100 degrees

4) Latent heat required to convert the water at 100 degrees to steam.

The amount of energy required in each process is as under

1)

where

' is specific heat of ice =

2) Amount of heat required in phase 2 equals

3) The amount of heat required to raise the temperature of water from 0 to 100 degrees centigrade equals

where

' is specific heat of water=

4) Amount of heat required in phase 4 equals

Thus the total heat required equals