States of Matter and Heat Transfer

The state of matter with the highest kinetic energy.

Answer explanation

The state of matter with the highest kinetic energy is plasma. In plasma, particles are highly energized and move freely, resulting in greater kinetic energy compared to solids, liquids, and gases.

The process by which a liquid turns into a vapor at all temperatures.

Answer explanation

The process described is called evaporation, which occurs when molecules at the surface of a liquid gain enough energy to enter the vapor phase, happening at all temperatures, not just at boiling point.

The process of converting a vapor directly into a solid.

Answer explanation

The process of converting a vapor directly into a solid is called deposition. This occurs when vapor molecules lose energy and transition into a solid state without becoming liquid first.

The unit of heat energy.

Answer explanation

The unit of heat energy is the joule (J). It quantifies the amount of energy transferred as heat. Other units like calories are also used, but joules are the standard SI unit.

The process of converting a solid into a liquid.

Answer explanation

The process of converting a solid into a liquid is called melting. This occurs when a solid absorbs heat, causing its particles to gain energy and transition into the liquid state.

Which of the following is an example of latent heat?

• Change in size of a body

• Change in temperature of a body

• Melting of ice at 0°C

• Heating of water

Answer explanation

Latent heat refers to the heat absorbed or released during a phase change without a change in temperature. The melting of ice at 0°C is a classic example, as it involves the absorption of heat to change from solid to liquid.

What happens to kinetic energy when a substance is heated?

• It decreases

• It increases

• It remains the same

• It is converted to potential energy

Answer explanation

When a substance is heated, its particles gain energy and move faster, which increases their kinetic energy. Therefore, the correct answer is that kinetic energy increases.

What is the process of converting a solid directly into a gas?

• Condensation

• Sublimation

• Freezing

• Deposition

Answer explanation

Sublimation is the process where a solid transforms directly into a gas without passing through the liquid phase, such as dry ice turning into carbon dioxide gas. This distinguishes it from condensation, freezing, and deposition.

What determines the rise in temperature of a material when heated?

• Volume of the material

• Quantity of heat supplied

• Color of the material

• Age of the material

Answer explanation

The rise in temperature of a material when heated is primarily determined by the quantity of heat supplied. More heat increases the kinetic energy of particles, leading to a higher temperature.

During which process does latent heat get absorbed without a change in temperature?

• Freezing

• Melting

• Condensation

• Boiling

Answer explanation

During melting, a substance absorbs latent heat to change from solid to liquid without a temperature change. This is distinct from freezing, condensation, and boiling, where temperature changes occur.