Melting and boiling

The energy required for a change of state is called

• chemical energy.

• state energy.

• latent energy.

• heat.

Which of the following types of energy remains constant during a change of state?

• Internal energy

• Potential energy

• Kinetic energy

If a substance expands on melting, increased pressure acting on it will

• increase its melting point.

• decrease its melting point.

• not change its melting point.

The reversed process of melting is

• freezing.

• condensation.

• sublimation.

Tags

NGSS.MS-PS1-4

The boiling point of water in a pressure cooker is raised by

• increasing the volume of water in the cooker.

• increasing the internal volume of the cooker.

• increasing the pressure in the cooker.

• increasing the pressure outside the cooker.

Which of the following changes occurs when water is freezing?

• Temperature of water rises.

• Temperature of water decreases.

• Temperature of water is constant.

Which of the following changes in phase involves the release of latent heat?

• Freezing of water

• Vaporisation of water

• Melting of ice

The specific latent heat of fusion is absorbed by a substance when it changes from

• a liquid to a gas.

• a gas to a liquid.

• a solid to a liquid.

• a liquid to a solid.

The latent heat of fusion supplied to a substance is used

• to keep its particles in their fixed positions.

• by particles to break away from their fixed positions.

• to increase the average speed of its particles in their random motion.

• to decrease the average speed of its particles in their random motion.

At –39^oC, liquid mercury solidifies without a change of temperature.

Which row shows whether the mercury absorbs or releases energy and what happens to the bonds between the mercury atoms?

• Energy: absorbed; bonds between atoms: stronger

• Energy: absorbed; bonds between atoms: weaker

• Energy: released; bonds between atoms: stronger

• Energy: released; bonds between atoms: weaker