Question

____ is the change of state directly from a solid to a gas. The reverse is called ____ which is the change directly from a gas to a solid.

Option 1: Sublimation; Deposition
Option 2: Evaporation; Condensation
Option 3: Melting; Freezing
Option 4: Vaporization; Precipitation

Answer 1

The change of state directly from a solid to a gas is called sublimation, while the change from a gas directly to a solid is known as deposition. Dry ice sublimation and frost formation are examples of sublimation and deposition, respectively.

Step-by-step explanation:

​Sublimation is the change of state directly from a solid to a gas. The reverse process is called deposition, which is the change directly from a gas to a solid. Therefore, the correct answer to the student's question is Option 1: Sublimation; Deposition. During sublimation, there is a measurable energy change as the substance absorbs energy to transition from solid to gas phase. This process can be observed in the sublimation of dry ice (solid CO₂) at room temperature. The reverse process, deposition, is exemplified by the formation of frost from water vapor in the air.