Specific Heat Capacity and Calorimetry - SS2 Physics Lesson Note

Specific heat capacity refers to the amount of heat energy required to raise the temperature of a substance by a certain amount. It is defined as the heat energy transferred per unit mass per degree Celsius (or Kelvin) change in temperature. Calorimetry, on the other hand, is the experimental measurement of heat transfer during a physical or chemical process. It involves the use of a calorimeter, a device that is designed to measure the heat exchanged between a system and its surroundings.

Specific Heat Capacity:

Specific heat capacity (C) is a property of a substance that quantifies its ability to store or release heat energy. It is defined as the amount of heat energy (Q) required to raise the temperature (ΔT) of a given mass (m) of a substance. The formula for specific heat capacity is given by: Q = m × C × ΔT. The SI unit for specific heat capacity is J/(kg·°C) or J/(kg·K).

Calorimetry:

Calorimetry is the experimental technique used to measure the heat exchanged between a system and its surroundings. A calorimeter is a device used in calorimetry to measure heat changes during a physical or chemical process. The principle of calorimetry is based on the fact that the heat energy transferred during a process is equal to the heat energy absorbed or released by the surroundings. Calorimetry involves measuring temperature changes and using them to calculate heat transfer. Two common types of calorimeters are constant-pressure calorimetry (also known as coffee cup calorimeters) and constant-volume calorimetry (also known as bomb calorimeters). In a calorimetry experiment, the heat absorbed or released by a substance is determined by measuring the temperature change and using the equation

Q = m × C × ΔT.

Calorimetry and the concept of specific heat capacity have various practical applications, including:

-       Determining the specific heat capacities of substances for engineering and thermodynamics calculations.

-       Monitoring and controlling temperature changes in industrial processes.

-       Designing efficient heating and cooling systems for buildings and appliances.

-       Investigating chemical reactions and their heat effects.

-       Studying the thermal behaviour of materials and substances in scientific research.

By understanding specific heat capacity and employing calorimetry techniques, scientists and engineers can gain insights into the thermal properties of substances, optimise energy usage, and design effective heat transfer systems.