Why is absolute zero important in the PV = nRT formula?

[Peter G.]

Hi,

Today in school I performed an experiment that went like this:

We had a capillary tube with trapped air on the bottom, the top part was open to the atmosphere and, in between, there was some sulphuric acid.

We heated the capillary tube and recorded the increase in volume of the trapped air and the temperature.

We were trying to check I believe how an increase in temperature will cause an increase in pressure, moving the sulphuric acid upwards, increasing the volume until the pressure outside was equal to that "inside".

We then went to the computer lab and plotted the relation between volume and temperature and tried to find absolute zero...

I didn't understand that... Why would we graph the temperature against volume and try and find absolute zero. Why do this experiment to determine the absolute zero?

I believe because absolute zero is when volume is = 0. But why is it equal to zero, at least in an ideal gas, which I am studying.

Thanks,
Peter G.

 

[Quinzio]

There's a famous formula $$PV = nRT$$.

Just google it.