Factors that affect gases

Factors that affect gases Pressure Force exerted when particles collide with their container Volume Amount of space or size of the container Temperature Average kinetic energy or “speed” of the particles Moles Amount or number of particles

Relationships All of the factors interact and are dependent on each other When you change one factor, it changes another factor.

Pressure Relationships What happens to the number of collisions if you increase the size of the container? (speed and number are constant) What happens to the number of collisions if you increase the speed of the particles? (size and number are constant) What happens to the number of collisions if you add more particles? (size and speed are constant)

Volume Relationships Imagine the container is a balloon… What happens to the size of a container if the particles speed up? (collisions and number are constant) What happens to the size of a container if you add more particles? (collisions and speed are constant)

Temperature Relationships What happens to the speed of the particles if you add more particles? (collisions and size are constant)

Gas Laws show relationships Boyle’s Law – Pressure and Volume P1V1 = P2V2 Inverse relationship – one goes up, other goes down Charles’ Law – Volume and Temperature V1 / T1 = V2 / T2 Direct relationship – one goes up, other goes up

Gas Laws show relationships Gay-Lussac’s Law – Pressure and Temperature P1 / T1 = P2 / T2 Direct relationship – one goes up, other goes up Avagadro’s Law – Volume and moles V1 / n1 = V2 / n2

Gas Laws show relationships These are in your Reference Tables. Combined Gas Law – Pressure, Volume, and Temperature P1V1 = P2 V2 T1 T2 Ideal Gas Law P1V1 = P2 V2 or PV = nRT T1 n1 T2n2 R is the Universal Gas Constant

Mixtures of Gases Dalton’s Law of Partial Pressures Total pressure is equal to the sum of the parts PT = P1 + P2 + P3 + … Most often used when gases are collected over water… Gas’s pressure + Vapor Pressure of Water = Pressure reading

Rate of Effusion Effusion is the escape of a fluid through a small opening Graham’s Law of Effusion states that the rate of effusion is inversely proportional to the square root of the molar mass. R1 / R2 = √(MM2) / √(MM1)