Chem(4.1)-Combined Gas Laws+Avogadro's law

Combined gas law formula

P1V1/T1=P2V2/T2

How to solve gas law problems

1. List all variables

2.Cross out the constant in the combined gas law formula if needed

3.Make unit conversions if needed (eg.degrees celsius to kelvin)

4.Substitute values into the formula with units

5.Give answer with proper unit+sig digs

How KMT explains why only gases are compressible

-Distance between molecules in a solid are only 1 molecule apart

-Distance between molecules in a liquid are only slightly bigger than 1 molecule apart

-Distance between molecules in gas are 20-30x the size of molecules (most volume in a gas is empty space)

How KMT explains gas pressure

-Pressure comes from gas molecules colliding with the walls of the container

-Pressure is the total force of the gas’ particle collisions distributed over the area of the container’s walls (P=F/A)

How KMT explains Boyle’s law

-Decreased volume causes more collisions with the container wall, increasing pressure

-If P=F/A, Decreasing volume also decreases A, creating a bigger P value

How KMT explains Charles’ law

-Increased temp. in a set pressure causes molecules to move faster, causing increased volume

Person who made Law of combining volumes

Gay-Lussac

Law of combining volumes

-When pressure + temp. are constant, volumes of gaseous reactants/products are in simple ratios of whole numbers

-Allows coefficients to be added when balancing a chemical equation

Avogadro’s law

Equal volumes of gases (with pressure and temp. as constant)= Equal number of moles