What is a gas?
And how is it different from being in solid or liquid state?
The key thing about being in gaseous state is that a lot of VOLUME or SPACE is being occupied (as seen by the purple gas).
Because gas particles are far more spread out than liquid or solid particles, they take up a lot a lot more space!
This can be seen in the use of airbags to protect car occupants in the event of a crash!
At airbags make use of a solid called Sodium Azide which is needed in very small amounts. Once ignited, it would produce nitrogen gas that would inflate the airbag.
Because the volume of a gas is a lot larger than volume occupied by a solid, you notice Sodium Azide can be hidden in the driving wheel nicely and blows up into a very big bag as in this exciting video below:
Now that we understand gases occupy BIG volume,
the next interesting thing is that the same amount of any gas of any type occupy the same volume!
Whether it is Helium or Oxygen or whoever, as long there is 1 mol of the particles present as a gas, it will take up a volume of 22.4dm3
Why is that so? Isn’t Carbon Dioxide heavier and Bigger than Oxygen or Helium? Why does it occupy the same volume as them?
The reason is because each gaseous particle claims a certain amount of volume or parking lot for itself, no matter how big or small it is.
How it does control that volume of space?
By actively bouncing around and colliding with others that come near!
To bounce around and collide with other gas particles and push them away, gas particle need Kinetic Energy.
And Kinetic Energy is related to temperature.
So the higher the temperature, the bigger the volume occupied by a gas particle!
This is why
1 mole of gas particles occupy 22.4dm3 at zero degree celsius,
1 mole of gas particles occupy 24.0dm3 at room temperature!
Now that you are familiar with how moles and volume relate to each other, this video teaches you how to solve exam questions!