Introduction To Specific Heat Capacity

What is the specific heat capacity?

The specific heat capacity is a property that quantifies the amount of heat energy required to raise the temperature of a unit mass of a substance by one degree Celsius. It is a fundamental concept in thermodynamics and is critical for understanding how various materials respond to heat.

How is the specific heat capacity calculated?

The specific heat capacity(cc) of a substance is the quantity of heat required to raise the temperature of a unit mass of that substance by one degree Celsius (or one Kelvin). The equation for specific heat capacity is:

Q=m*c*ΔT

Where:

• Q = supplied heat energy (Joules, J)
• m = mass of the substance (kg)
• c = specific heat capacity (J/kg-°C or J/kg-K)
• ΔT = change in temperature (°C or K)

Specific heat capacity vs. heat capacity

Although both terms refer to heat energy, specific heat capacity and heat capacity are distinct concepts. The heat capacity is the amount of heat energy required to change the temperature of an entire object, irrespective of its mass. In contrast, the specific heat capacity is the heat required to raise the temperature of a unit mass of a substance by one degree Celsius.

Examples of specific heat capacity

Different materials exhibit distinct specific heat capacities. An example:

• Water possesses a high specific heat capacity, thereby absorbing a significant amount of heat with minimal temperature change.
• Aluminium has a lower specific heat capacity than water, and consequently, it heats up and cools down more quickly.
• Iron has an even lower specific heat capacity, thereby making it suitable for applications that require fast temperature variations.

The following table shows the specific heat capacities of various substances:

Further information is available at Stanford Advanced Materials (SAM).

Frequently Asked Questions

Which factors influence the specific heat capacity?

The influencing factors include the material’s molecular structure, its phase, and temperature.

Why does water have a high specific heat capacity?

Due to the presence of hydrogen bonds, water requires a larger amount of heat energy to achieve the same temperature increase.

How is the specific heat capacity used in real life?

It is utilised in the design of heating and cooling systems, in cooking, and in analysing climate dynamics.

Can specific heat capacity change with temperature?

Yes, in some materials the specific heat capacity varies with temperature.

Is the specific heat capacity the same for all states of matter?

No, different states (solid, liquid, gaseous) of the same substance can exhibit different specific heat capacities.