Sublimation- the change from a solid directly to a gaseous state

Deposition- the change from a gas directly to a solid state.

~

Phase transitions are the transitions of a physical state change. The 3 phases, vaporization & condensation, melting & freezing, and sublimation & depositions, are 6 ways a substance can change its physical state. As the gas phase molecules, from vaporized liquid, move around in a closed container, sometimes they'll collide with the condensed phase, which becomes condensation. Vaporization occurs when you can see the amount of liquid decrease and the scent of certain vapors are noticeable.

Intermolecular forces are the forces between neighboring molecules. If the intermolecular forces in a liquid are strong, then it has a low vapor pressure, and vice versa, low intermolecular forces in a liquid means it has a high vapor pressure. However, if the intermolecular forces in a solid are strong, the solid has a high melting temperature.

When heat is added to boiling water, although the state may change, the temperature won't because it's at it's peak temperature, it's boiling point. Like the boiling water, if heat is added to ice, the state changes, but the temperature won't because the ice is at its freezing point. The boiling of a liquid occurs throughout the entire liquid substance whereas evaporation is only on the surface.

In the melting process of a solid, the added energy from the heat overcomes the molecules, beginning the process of the solid turning to liquid, at which, the temperature is constant until it becomes a liquid. The heat needed for vaporization requires more energy than what is needed for the enthalpy of fusion. Then there is sublimation, which occurs when a solid disappears into a gas without becoming a liquid first, for example, dry ice. Deposition is the opposite of sublimation, where a gas changes directly to a solid, frost being an example of deposition.

~

The Clausius-Clapeyron equation: P=Ae(^)(−ΔHvap/RT) describes the relation between a substance's vapor pressure and the temperature where ΔHvap = enthalpy(heat) of vaporization for the liquid, R= gas constant, A= constant whose value depends on the chemical identity of the substances, T= temperature (K)

lnP=−(ΔHvap/RT)+lnA is a linear equation rearranged form of the Clausius-Clapeyron equation. Its corresponding linear equations are lnP1=−(ΔHvap/RT1)+lnA and lnP2=−(ΔHvap/RT2)+lnA, when set equal to each other, they can be combined into the equation ln(P2/P1)=(ΔHvap/R)(1/T1−1/T2)