Question

How are heat, internal energy, and thermal energy related to each other?

Short answer

#Question# Explain the relationship between heat, internal energy, and thermal energy. #Answer# Heat is the energy transfer due to a temperature difference, internal energy is the total energy contained within a system, and thermal energy is a form of internal energy related to the random motion of atoms and molecules. Heat has a direct impact on the change in internal energy and creates a change in thermal energy, which results in a change in temperature.

Step-by-step solution

Define Heat

Heat is the energy transferred between two systems or between a system and its surroundings due to a temperature difference. Heat can flow from a hotter body to a colder one or vice versa. Heat always flows in the direction that reduces the temperature difference. The SI unit of heat is the Joule (J).

Define Internal Energy

Internal energy (U) is the total energy contained within a system. It consists of all the energy associated with the system's atoms and molecules such as kinetic energy and potential energy. Kinetic energy is the energy of motion, and potential energy is the energy of the interactions between these atoms and molecules. The unit of internal energy is also Joule (J).

Define Thermal Energy

Thermal energy is a form of internal energy that arises due to the random motion of atoms and molecules in a substance. It is also known as heat energy. Thermal energy depends on the temperature and quantity of the substance; the higher the temperature or quantity, the greater the thermal energy. The unit of thermal energy is Joule (J).

Relationship between Heat and Internal Energy

Heat is the energy transfer between systems due to a temperature difference, while internal energy is the total energy contained within a system. When heat is added to a system, the internal energy of the system typically increases and the temperature rises (unless the energy is being used for a phase change). Similarly, when heat is taken away from a system, the internal energy decreases, and the temperature lowers.

Relationship between Thermal Energy and Internal Energy

Unlike heat, which is an energy transfer, thermal energy is a form of internal energy that arises from the random motion of atoms and molecules in a substance. Thermal energy contributes to the internal energy, but it's not the only factor. Other forms of energy that contribute to internal energy include chemical energy (related to bond formation and breaking) and nuclear energy (related to nucleus interactions).

Conclusion

In summary, heat is the energy transfer due to a temperature difference, internal energy is the total energy contained within a system, and thermal energy is a form of internal energy that is related to the random motion of atoms and molecules. Heat has a direct impact on the change in internal energy and creates a change in thermal energy, which results in a change in temperature.