🔁 1. Definition of Sublimation
The direct change of a solid into vapours without passing through the liquid state is called sublimation.
✨ 2. Common Examples of Sublimation
Naphthalene balls: Used to keep insects away from woolen clothes; they disappear because they sublime.
Solid air fresheners: Release scent directly from solid to gas.
⚡ 3. Energy Requirement for Sublimation
The energy needed for sublimation comes from within the substance. The substance absorbs energy from its surroundings. This energy overcomes the attractive forces between neighbouring molecules, allowing them to escape into the vapour phase.
❄️ 4. Definition of Deposition
Deposition is the reverse process of sublimation. A gas changes directly into a solid without becoming liquid.
📌 5. Quick Check Insights
Does the change in temperature occur during evaporation? Evaporation causes cooling because energy is absorbed from the surroundings.
Does ice sublime? Yes, ice can sublime (e.g., snow disappearing without melting).
Other examples: Sublimation → Iodine crystals turning into purple vapour on heating. Deposition → Snow formation directly from water vapour in clouds.
🖨️ 6. Applications of Sublimation
(a) Solid Air Fresheners
Scented solid substance sublimes into sweet-smelling vapours. Can happen with or without heating. The vapours spread in the room and mask unpleasant odours.
(b) Sublimation Printing
A design is printed onto fabric using heat and sublimation inks.
Steps: 1. Print design on special paper using sublimation inks. 2. Place paper on fabric; apply heat and pressure. 3. Ink converts into vapour, enters open pores of fabric (heat opens pores). 4. Ink cools and returns to solid form inside fabric.
Advantage: Printing is permanent and does not fade because ink is embedded inside the fabric, not just on top.
Uses: Print-on-demand T-shirts, ceramic, wood, and metal with special coating.
“Solid to Gas = Sublime (Skip the Liquid Line)”
“Gas to Solid = Deposit (Frosty Gift)”
💡 Remember: Dry ice (solid CO₂) disappears without puddle = sublimation.
💡 Frost on a winter morning = deposition (water vapour → ice crystals).
🎓 Acronym: D.S. duo — “Direct to Vapour = Sublimation, Direct to Solid = Deposition”.
🧪 Visualize: Iodine crystals heating produce purple vapour (sublimation) — reverse: vapour to crystal on cold surface (deposition).