Sublimation

Sublimation

is the direct phase transition of a solid

to a gas without passing through the liquid phase.

Sublimation

This occurs when a substance's vapor pressure

exceeds atmospheric pressure at a given

temperature.

Endothermic process

(requires heat absorption)

Sublimation

Occurs in low-pressure environments or at

specific temperatures.

Sublimation

Common in substances with weak intermolecular

forces, allowing easy transition to gas.

weak

Sublimation is Common in substances with _ intermolecular

forces, allowing easy transition to gas.

Iodine (I2)

Dry Ice (CO2 solid)

Naphthalene (mothballs)
Caffeine

Examples of Sublimating Substances 4

Iodine (I2)

Produces violet vapors.

Dry Ice (CO2 solid)

Converts directly to CO2 gas.

Naphthalene (mothballs)

Slowly vaporizes at

room temperature.

Naphthalene

_ (mothballs)

Caffeine

Can be purified by sublimation under

reduced pressure.

Sublimation Applications

Purification of organic compounds (e.g., caffeine,

benzoic acid).

Sublimation Applications

Freeze-drying (lyophilization) → Used in food

preservation and pharmaceuticals.

Sublimation Applications

Deposition techniques in material science (e.g.,

thin-film coatings).

caffeine,

benzoic acid

Sublimation is Purification of organic compounds (e.g., _ 2).

Freeze-drying (lyophilization)

→ Used in food

preservation and pharmaceuticals.

Freeze-drying

lyophilization

thin-film coatings

Sublimation is Deposition techniques in material science (e.g.,

_).

Temperature
Pressure

Intermolecular Forces

Factors Affecting Sublimation 3

Temperature

Higher _ increases

sublimation rate.

sublimation

Higher temperature increases

_ rate.

Temperature

Higher temperature increases

sublimation rate.

Pressure

Lower pressure favors sublimation.

Pressure

Lower _ favors sublimation.

sublimation

Lower pressure favors _.

Intermolecular Forces

Weak forces (e.g., van der

Waals) promote sublimation.

Weak

_ forces (e.g., van der

Waals) promote sublimation.

sublimation

Weak forces (e.g., van der

Waals) promote _.