Question

1. which of the following best defines the phase change of melting? *

○ the change of a solid into a liquid.
○ the change of a liquid into a gas.
○ the change of a gas into a liquid.
○ the change of a gas directly into a solid.

1. which of the following is an example of melting? *

○ dew forming on grass overnight.
○ a puddle of water disappearing on a hot day.
○ an ice cube turning into liquid water at room temperature.
○ water vapor turning into frost on a cold window.

Explanation:

Question 1

To determine the best definition of melting, we recall the phase change terms: melting is the process where a solid transitions to a liquid. The second option is evaporation (liquid to gas), the third is condensation (gas to liquid), and the fourth is deposition (gas to solid).

We analyze each option: Dew forming is condensation (gas to liquid). A puddle disappearing is evaporation (liquid to gas). An ice cube (solid) turning to liquid water is melting. Water vapor to frost is deposition (gas to solid).

Answer:

The change of a solid into a liquid.

Question 2