Which labeled change (A, B, C, or D) involves both condensation and freezing?

The diagram illustrates the phase changes of water:

• Water is the liquid state.
• Steam is the gaseous state.
• Ice is the solid state.

Let's identify each labeled change:

• A: Steam $\longrightarrow$ Water. This is condensation (gas to liquid).
• B: Water $\longrightarrow$ Ice. This is freezing (liquid to solid).
• C: Ice $\longrightarrow$ Steam. This is sublimation (solid to gas).
• D: Steam $\longrightarrow$ Ice. This is deposition (gas to solid).

The question asks which change (A, B, C, or D) can involve both condensation and freezing.

• Condensation is the change from gas to liquid.
• Freezing is the change from liquid to solid.

For a process to involve both condensation and freezing, it must start from a gas, pass through a liquid phase, and end as a solid. This sequence is:
Gas $\xrightarrow{\text{Condensation}}$ Liquid $\xrightarrow{\text{Freezing}}$ Solid

Let's examine the options:

• A (Steam to Water): This is only condensation. It does not involve freezing.
• B (Water to Ice): This is only freezing. It does not involve condensation.
• C (Ice to Steam): This is sublimation. It involves neither condensation nor freezing.
• D (Steam to Ice): This represents the overall change from a gas (steam) to a solid (ice). While this change can occur directly as deposition, it can also occur indirectly by first condensing to water (condensation) and then freezing the water into ice (freezing). Therefore, the change from steam to ice can involve both condensation and freezing.

The correct change is D.