Phases of Matter

Quimica

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Phases of matter

Solid: below melting point

Liquids: overcome the bonds and intermolecular forces. Solid melts

Gases:

* Liquid vaporizes.

* Collection of particles (collide w/each other) in constant, rapid and random motion→Brownian motion.

* Fills any container (no shape)→ 2nd law of thermodynamics

* Pure gas: pressure, temp, volume and number of moles

* Ideal gases should meet ALL of the assumptions of the kinetic molecular theory (particles of a gas are in random, constant, straight-line motion.)

* Incorrect physical property/Kinetic molecular theory: gas molecules are attracted to each other but not repelled. Gases are tiny particles separated by areas of empty spaces.

Sublimation: from solid to liquid

Plasmas: extreme high temp

Kinetic theory of gases: the only contribution to the energy of a gas arises from the kinetic energy of the gas particles

Kinetic energy theory: relate pressure directly to the average speed of the gas particles

Max Boltzman distribution revisited: velocity distribution of gas molecules of thermal equilibrium (probability and velocity). Depend on the total speed of the particle (mean speed, most probable speed, root-mean-square speed)

Collisions:

* Most fundamental processes in chemistry that provide the mechanism (chemical reactions and energy transfer) occurred in a gas

* Collisions frequency: number of collisions a molecule undergoes per unit of time

* Kinetic energy: calculate the collisions frequencies for 2 cases: collisions with the container walls and intermolecular collisions

Characteristics of Liquids:

* T ↓ as Ke ↓

* Intermolecular distances ↓ until gas → liquid

* Shape: not constant

* Volume: constant at constant T, ↑ 10% when solid melts

* Molecules: move slower

* Crystal: regular arrangement of molecules in solid state

* Compression: small extent

Properties of Liquids:

* Vapor pressure:

* Boltzmann’s distribution law: most abundant particles are those with average Ke

* Vapor-liquid equilibrium: molecules evaporating= vapor molecules returning to liquid

* Boiling point: T at which boiling takes place

* Heat of vaporization: energy required converting liquids into gases at STP

* Heat of condensation: when gases condense into liquids the same amount of heat is released

* Distillation: process of vaporizing and condensing their vapors in another vessel (purify liquids)

* Fractional distillation: liquid mixture separated into its components using the differences in boiling points

* Freezing point: T of solidification at 1 atm

* Phase equilibrium:

Properties of Solutions:

* Solution: 2 or multi-component system (solvent + solute)

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