Internal energy

Question 1

What is internal energy?

Answer 1

The sum of the randomly distributed kinetic and potential energies of atoms or molecules within the substance.

Question 2

How does increasing temperature change internal energy?

Answer 2

Increasing the temperature of a body will increase its internal energy. As the temperature increases, the average kinetic energy of the atoms or molecules inside the body increases.

Question 3

How does potential energy increase?

Answer 3

When a substance changes phase the temperature does not change however the electrostatic potential energy increases significantly and hence internal energy increases.

Question 4

What is the electrostatic potential energy at gas phase?

Answer 4

The electrostatic potential energy is zero because there are negligible electrical forces between atoms or molecules.

Question 5

What is the electrostatic potential energy at liquid phase?

Answer 5

The electrostatic forces between atoms or molecules give the electrostatic potential energy a negative value, means that energy must be supplied to break the atomic or molecular bonds

Question 6

What is the electrostatic potential energy at solid phase?

Answer 6

The electrostatic forces between atoms or molecules are very large, so the electrostatic potential energy has a large negative value