Understanding Changes in Internal Energy and Physical States of Matter

The video explains the concept of internal energy, which is the sum of kinetic and potential energy of particles in an object. It describes how heating affects a solid, causing particles to vibrate more and increase temperature until the melting point is reached. During state changes, energy increases potential energy, keeping temperature constant. Once in liquid form, further heating leads to boiling, where particles overcome attractions and transition to gas. In the gas state, particles move freely, and continued heating raises kinetic energy and temperature.

What happens to the internal energy of an object when it is heated?

• It decreases.

• It increases.

• It fluctuates randomly.

• It remains constant.

During the melting of a solid, what happens to the temperature?

• It increases.

• It remains constant.

• It decreases.

• It fluctuates.

What type of energy increases when a solid changes to a liquid?

• Potential energy

• Thermal energy

• Electrical energy

• Kinetic energy

What occurs at the boiling point of a liquid?

• Temperature decreases.

• Particles completely overcome attractions.

• Particles move closer together.

• Particles lose energy.

After a liquid turns into a gas, what happens if thermal energy continues to be supplied?

• The gas solidifies.

• The kinetic energy of particles increases.

• The potential energy decreases.

• The gas condenses.