Quiz: Changes of State — 4 questions

1. What change of state occurs when liquid water becomes steam?

A. Condensation from gas to liquid

B. Freezing from liquid to solid

C. Deposition from gas to solid

D. Vaporization from liquid to gas

Answer: (D)

Explanation

Vaporization is the change from a liquid into a gas, as happens when water becomes steam. Condensation describes the reverse direction, from gas to liquid.

2. Which change of state occurs when a solid changes directly into a gas without becoming a liquid?

A. Sublimation

B. Deposition

C. Freezing

D. Melting

Answer: (A)

Explanation

Sublimation is the direct change from solid to gas. Melting instead changes a solid into a liquid before any further state change.

3. Which statement correctly distinguishes evaporation from boiling?

A. Evaporation changes gas into liquid, while boiling changes liquid into solid.

B. Evaporation occurs below 0°C, while boiling occurs above 100°C.

C. Evaporation occurs at 100°C, while boiling can occur at any temperature.

D. Evaporation can occur at any temperature, while boiling occurs at 100°C.

Answer: (D)

Explanation

Evaporation can happen at any temperature, whereas boiling occurs at 100°C under ordinary conditions. The reverse state change from gas to liquid is condensation, not evaporation.

4. Why does water boil at a temperature below 100°C at higher altitudes?

A. Reduced sunlight gives the water a higher boiling point.

B. Thinner air creates lower pressure around the water.

C. Higher altitude increases the pressure inside the water.

D. Cooler mountain air changes water into a different substance.

Answer: (B)

Explanation

At higher altitudes, the air is thinner and the surrounding air pressure is lower, so water boils below 100°C. Lower pressure, rather than reduced sunlight, explains the lower boiling temperature.