# Why is specific heat capacity important?

Oct 8, 2015

It has importance in terms of energy, time and costs involved in changing temperatures of objects.

#### Explanation:

Specific heat capacity is a measure of the amount of heat energy required to change the temperature of 1 kg of a material by 1 K.

Hence it is important as it will give an indication of how much energy will be required to heat or cool an object of a given mass by a given amount. This will give information as to how long the heating or cooling process will take under a given supply, as well as the cost implications thereof.

Let me give you a brief example :
The specific heat capacity of water is about 4200 J/kg.K
This means that it will take 4200 J of energy to raise the temperature of 1 kg of water by 1 degree kelvin.
Suppose now you want to boil 2 kg of water in a kettle from room temperature of ${20}^{\circ} C$ to ${100}^{\circ} C$
This will require $m c \Delta T = 2 \times 4200 \times 80 = 672 k J$of energy to achieve.
Suppose the kettle has a power rating of 2KW.
Then the time taken to boil this mass of water will be $t = \frac{W}{P} = 336 s = 5 , 6 \min s$
Suppose the power provider charges tariffs of R1,50/Kwh unit (South African rates), then this will cost $\frac{0 , 672 M J}{3 , 6 M J} \times R 1 , 50 = R 0 , 28$

Additional applications would also include in heat conduction, convection and radiation, length and volume expansions, phase changes, etc.