Introduction to Heat Capacity

You’ve probably noticed that the sand is extremely cool in the morning and extremely hot in the afternoon when you go to the beach, but the water’s temperature doesn’t seem to change at all. Water and sand are both subjected to the same amount of solar energy, but the differences in their physical properties cause them to react in different ways. A contributing factor to this phenomenon is that water has a significantly higher heat capacity than sand, which simply means that it takes significantly more energy to raise the temperature of water than it does of sand.

Recognizing the Effects of Heat

To comprehend heat capacity, we must first comprehend the concept of heat. When we talk about heat, we’re usually referring to whether or not something feels hot or cold to the touch. Due to the fact that heat is actually a form of energy that flows from objects with higher temperatures to objects with lower temperatures, this is the case. When my hand touches a hot coffee mug, the mug will feel warm because the energy from the mug is being transferred to my cooler hand through conduction. In a similar manner, when I pick up a glass of ice water, the heat from my hand is transferred to the glass, making the glass feel cold to the touch.

Internal Energy

Internal energy is the sum of kinetic and passive energy contained within an object when compared to the energy contained within an object at rest. We already know that heat is the transfer of energy that occurs as a result of a temperature differential between two objects. An object can therefore contain internal energy but not heat, despite the fact that both are possible. The joule is the SI unit for heat because it is a form of energy.

What is the definition of Heat Capacity?

The heat capacity of a substance is defined as the amount of heat required to raise or lower its temperature by one degree Celsius.

When it comes to heat, thermodynamics is concerned to its full extent. Heating means energy in transit, according to the dictionary definition. The measurement of heat before the development of thermodynamic laws was based on the assumption that heat was a measure of an invisible fluid, caloric, present in any matter. The ability of a substance to retain this fluid was referred to as the heat capacity of that substance at the time of its discovery. As thermodynamics progressed and the relationship between heat transfer and temperature became more clear, the definition of heat shifted accordingly.

Modern thermodynamics defines heat as a measure of a system’s total internal energy, which is measured in degrees Celsius. For the purpose of quantifying both the heat energy associated with matter and its dependence on temperature, two properties were established. Specific heat capacity and heat capacity of the system were the names given to these characteristics.

Formula for Heat Capacity

Heat energy is a measure of a system’s total internal energy, which is measured in joules. This includes both the total kinetic energy of the system as well as the potential energy of the individual molecules in the system.

It has been demonstrated that the internal energy of a system can be changed either by supplying heat energy to it or by performing work on it, respectively.

It has been discovered that the internal energy of a system increases as the temperature of the system rises. Internal energy increases as a function of temperature differences, the amount of matter present, and other factors.

The amount of heat energy required to raise the temperature of a given quantity of matter by one degree Celsius is defined as the heat capacity of the matter in question.

The heat capacity of a given matter is dependent on the size or quantity of the matter, and as a result, it is an extensive property. The unit of heat capacity is the joule per Kelvin or the joule per degree Celsius, depending on the temperature.

Mathematically,

Q=CΔT

Where Q is the amount of heat energy required to cause a temperature change of ΔT and C is the amount of heat capacity available in the system under consideration.

Specific Heat Capacity 

To conduct thermodynamic studies, scientists required a quantity that was not dependent on the quantity or size of the matter under consideration. This requirement led them to develop the concept of specific heat capacity. It is referred to as an intensive property because it is independent of the quantity or size of the matter being studied or measured. When it comes to any substance or matter, the specific heat capacity can be defined as the amount of heat energy required to raise the temperature of a unit mass of that substance or matter by one degree Fahrenheit. The following is how it is expressed mathematically:

Q= m c Δ T

Amount of heat energy required to change the temperature of a substance by one degree Celsius is denoted by Q, and specific heat capacity of the system is denoted by s.

Conclusion

Thermodynamics continues to play a significant role in our lives, whether directly or indirectly through the use of heat. In order to design new processes for reactions that have high efficiency and product yield, scientists and engineers use the laws of thermodynamics. The concepts of thermodynamics are applied by chemical and mechanical engineers in the design of heat engines that have high efficiency and produce higher output.