Properties of gases

Diffusion

The spontaneous spreading out of a substance due to the natural movement of it’s particles

What is Boyle’s law

At a constant temperature, the volume of a fixed mass of gas is inversely proportional to it’s pressure

P x V = constant

Charles law

At a constant pressure, the volume of a fixed mass of gas is directly proportional to the temperature in Kelvin

V/T = constant

Gay Lussac’s law of combining volumes

When gases react, the volumes of gases consumed in the reaction bear a simple whole number ratio to each other and to the volumes of any gaseous products of the reaction, with all volumes being measured under the sane conditions of temperature and pressure.

Avogadro’s law

Equal volumes of gases under the same conditions of temperature and pressure contain equal numbers of molecules

Combined gas law

(P1 x V1)/T1 = (P2 x V2)/T2 (1 usually equals STP)

Kinetic theory of gases

1. Gases are made up of particles, whose diameters are negligible compared to the distances between them.

2. There are no attractive or repulsive forces between gas molecules.

3. Gas molecules are in continuous rapid, random motion colliding with each other and the walls of the container.

4. All collisions are perfectly elastic.

5. The average kinetic energy of the particles is proportional to the Kelvin temperature

Ideal gas

A gas that follows all assumptions of the Kinetic Theory under all conditions of temperature and pressure.

How do real gases differ from ideal gases

There are attractive and repulsive forces between the particles

Diameters of gas molecules are not negligible compared to the distance between them

When are real gases closest to ideal gases

Under low pressure and high temperature

Equation of state for an ideal gas

PV = nRT