Specific heat capacity – Temperature changes and energy

The specific heat capacity of a material is the energy required to raise one kilogram (kg) of the material by one degree Celsius (°C). For instance, The specific heat capacity of water is 4,200 joules per kilogram per degree Celsius (J/kg°C). This means that it takes 4,200 J to raise the temperature of 1 kg of water by 1°C.
Change in the temperature of a system depends on:

• the mass of the material
• the substance of the material – its specific heat capacity
• the amount of energy put into the system

From the factors mentioned above, we can conclude, When a one-kilogram block of lead absorbs 1,000 J of heat, its temperature goes up. If it absorbs 2,000 J, the temperature rise is greater. However, if a two-kilogram block of lead absorbs 1,000 J, the temperature rise is not as much because the energy is divided among more particles. Also, if 1,000 J of energy is absorbed by a one-kilogram block of copper instead of lead, the temperature doesn’t rise as much.

Examples of Specific Heat Capacity

Substance	Specific Heat Capacity (J/g°C)	Explanation
Water	4.18	Water has a high specific heat, making it effective at storing and transporting thermal energy.
Aluminum	0.90	Aluminum heats up and cools down relatively quickly compared to water.
Iron	0.45	Iron has a lower specific heat, so it heats up and cools down faster than water.
Ethanol	2.44	Ethanol has a moderate specific heat capacity.
Glycerol	2.43	Glycerol is commonly used in some antifreeze solutions and has a specific heat capacity higher than metals but lower than water.

Thermal Energy

The amount of thermal energy stored or released as the temperature of a system changes can be calculated using the equation:

Change in thermal energy = mass × specific heat capacity × temperature change

This is when:

• change in thermal energy (ΔQ) is measured in joules (J)
• mass (m) is measured in kilograms (kg)
• specific heat capacity (c) is measured in joules per kilogram per degree Celsius (J/kg°C)
• temperature change (ΔT) is measured in degrees Celsius (°C)

Solved Problem

Suppose we have a 500-gram block of aluminum, and we want to calculate the change in thermal energy when its temperature increases by 10 degrees Celsius. The specific heat capacity of aluminum is 0.90 J/g°C.

Mass=500g
Specific Heat Capacity=0.90 J/g°C
Temperature Change=10 °C

Change in Thermal Energy=500g×0.90J/g°C×10°C = 4500J