Kinetic Theory And Gases Flashcards
What is a solid
It has strong forces of attraction holding the particles together in a fixed regular arrangement
The particles have little energy so can only vibrate in their fixed positions
What is a liquid
There are weaker forces of attraction between the particles the particles are close together but move past each other and form irregular arrangements they have more energy than the particles in a solid so can move in random directions but at low speeds
What is a gas
There are almost no forces of attraction between the particles they have more energy than liquids or solids and are free to movie in random directions at low speeds
What happens in a gas
They consist of very small particles which are constantly moving and colliding with each other and the walls of their container the particles hardly take up any space so most of the gas is empty space
What is absolute zero
It’s the coldest temperature you can get where there is no energy at all and the particles are still it’s called 0 kelvin it is equal to -273 degrees c
How to convert between Celsius and kelvin
0 kelvin is -273 Celsius
So 0 Celsius is 273 kelvin
You can never get a minus kelvin
What does it mean if kinetic energy is proportional to temperature
If you increase the temperature of a gas you give it’s particles more energy
If you double the temperature of a gas you double its kinetic energy
The kelvin temperature is directly proportional to the average kinetic energy of the particles
What is the kinetic theory
As gas particles move about they collide with each things
When they collide with something they exert a force on to it
In a sealed container they collide with the walls and create an outward pressure
The pressure depends on how fast the particles are going and how fast they hit the walls
What happens when a gas is at a constant pressure
It’s volume is proportional to its temperature
So if you heat up the gas it expands to take up a bigger volume
Volume 1 = volume 2 x temperature1 in K/temperature 2 in K
What happens when a gas is at a constant temperature
If you reduce the volume the pressure increases and if you put the gas into a bigger volume the pressure decreases
So pressure and volume are inversely proportional
V1 x p1 = v2 x p2
How can you investigate a constant pressure using a gas syringe
Half fill and Seal a gas syringe with a rubber bung
Heat using a Bunsen burner
As it heats the gas will expand bushing the plunger outwards
Since the plunger is free to move the pressure stays the same
How to use a gas syringe to investigate pressure and volume at a constant temperature
Attach a gas syringe half filled with air to a pressure sensor if you push the plunger you reduce the volume and the pressure will increase if you pull the plunger out you increase the volume and increase the pressure
What is the equation when none of the pressure volume and temperature are constant
P1v1/t1= p2v2/t1
Why are gases used in medicine kept under high pressure
The stored gas is at higher than 1 atmosphere or the pressure outside of the canister so that the flow rate is high
This means a lot of gas can be kept at a small volume
The canister will never completely empty because once the pressure inside is equal to the pressure outside the gas won’t leave the container
what is flow rate
The volume of gas per unit time released from a a gas bottle
Most gas bottles have a valve so the flow can be controlled
