Which process is the change from a solid directly to a gas?

Which process is the change from a solid directly to a gas?

• A. Condensation
• B. Sublimation
• C. Deposition
• D. Freezing

Answer: (B)

Sublimation is the solid-to-gas phase change. It happens when the particles in a solid gain enough energy to overcome the forces holding them in the solid lattice and escape directly into the air as a gas, skipping the liquid stage. This tends to occur at low pressures or when the solid’s vapor pressure is high at the given temperature. A familiar example is dry ice turning straight into carbon dioxide gas at room temperature. This differs from melting, where a solid becomes a liquid by absorbing energy; condensation, where a gas becomes a liquid; and deposition, where a gas becomes a solid.

Sublimation is the solid-to-gas phase change. It happens when the particles in a solid gain enough energy to overcome the forces holding them in the solid lattice and escape directly into the air as a gas, skipping the liquid stage. This tends to occur at low pressures or when the solid’s vapor pressure is high at the given temperature. A familiar example is dry ice turning straight into carbon dioxide gas at room temperature. This differs from melting, where a solid becomes a liquid by absorbing energy; condensation, where a gas becomes a liquid; and deposition, where a gas becomes a solid.