Physics: P1

Specific Heat Capacity

Specific heat capacity is the energy needed to raise the temperature of 1kg of material by 1'C.

Each material has its own value, which is a measure of how much energy it can hold. 

• The following equation is used to find the amount of energy required to find the amount of energy required to raise the temperature of an object by a certain amount.
• Energy(J) = Mass(kg) x Specific heat capacity (J/kg'C) x Temperature change('C)

Example 1. The specific heat capacity of copper is 387J/kg'C. Calculate how much hear energy is required to raise the temperature of a 5kg block of copper by 10'C. 

Use the formula.

=5kg x 387J/kg'C x 10'C = 19350

Specific Heat Capacity:

Example 2. It takes 29,800J if heat energy to raise the temperature of a 4kg block of aluminium by 8'C. Calculate heat capacity of aluminium.

Rearrange the formula.

Specific heat capacity = Energy divided by mass x temperature change

= 28,800 divided by 4 x 8 = 900J/kg'C

Specific Latent Heat:

• The amount heat energy required to melt or boil 1kg of a material is called the specific latent heat.

It depends on: 

• the material
• the state (solid,liquid,gas).

The energy required to boil or melt a certain mass of a material can be found using the following equation:

Energy (J) = Mass (kg) x Specific latent heat (J/kg)

Example 1. The specific latent heat of ice is 330,000J/kg. An ice sculpture with a mass of 10kg is left to melt on a hot day. Calculate the amount of energy required to melt the ice. Using the equation:

Energy = Mass x Specific latent heat

= 10 x 330 000 = 3 300 000J