- Fixed mass of gas
- Constant pressure
When we did the experiment in class, this is what we got:
The above graph looks strange because we could only do a range of temperatures from ice to steam.
Next we extended the line backwards until we had zero volume. You can't have less than zero volume so it must have the lowest possible temperature, ABSOLUTE ZERO.
Finally, we have the case where a new temperature scale is invented starting at ABSOLUTE ZERO. This graph passes through the origin (because we moved the origin!) so we get a proportional pattern
It means
- Volume is proportional to absolute (Kelvin) temperature
- Double the Kelvin temperature, double the volume
- V/T = a constant
- V1/T1 = V2/T2
It is explained by saying that molecules are moving faster at a higher temperature so they spread further apart.
Be prepared to draw extra lines on the graph through absolute zero for
- Higher constant pressure
- Lower constant pressure
