Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
The process of conversion of solid directly into gas is known as ____________.
Sublimation
Condensation
Evaporation
Deposition
Sublimation
Sublimation is the phase transition where a substance changes directly from the solid state to the gaseous state without passing through the intermediate liquid phase. This occurs when the vapor pressure of the solid equals the surrounding atmospheric pressure at a temperature below the triple point.
Sublimation is the phase transition where a substance changes directly from the solid state to the gaseous state without passing through the intermediate liquid phase. This occurs when the vapor pressure of the solid equals the surrounding atmospheric pressure at a temperature below the triple point.
Think of mothballs (naphthalene) disappearing from your closet over time without leaving any liquid residue; they 'vanish' into the air as vapor.
S-G-V: Solid to Gas is Vaporization (Sublimation).
╬ФHsubтАЛ=╬ФHfusтАЛ+╬ФHvapтАЛ тАФ representing enthalpy of sublimation as the sum of fusion and vaporization enthalpies.
This process occurs because the intermolecular forces in the solid are overcome by the absorption of thermal energy, allowing molecules to escape directly into the vapor phase. It is an endothermic process as energy is required to break the crystal lattice structure.
Sublimation occurs when the external pressure is lower than the triple point pressure of the substance.
It is a physical change, not a chemical reaction.
Common examples include dry ice (solid CO2тАЛ), iodine, and camphor.
Used for purification of volatile solid compounds.
Effective for freeze-drying food preservation.
Requires controlled pressure conditions for many substances.
Potential loss of mass if stored in open containers.
Dry ice for theatrical fog effects and industrial cooling.
Freeze-drying (lyophilization) in the pharmaceutical and food industry.
Triple point of CO2тАЛ is approximately 5.11 atm; at 1 atm, it sublimes at тИТ78.5circC.
Option B (Condensation) is gas to liquid. Option C (Evaporation) is liquid to gas. Option D (Deposition) is gas to solid.
A is correct тАФ Sublimation is the direct phase transition from solid to gas.
Remember that 'Deposition' is the exact reverse of 'Sublimation' (gas to solid); these are frequently tested together in competitive exams.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download тАв 100K+ Aspirants