Question

Sketch the graph of pV vs p when the temperature of the gas is constant. here p means pressure and V means volume - showing you the direct relationship b/w p and V (by using pV). how to sketch it???

Answer 1

We know that the Ideal gas equation is
`PV = nRT`
where
`P` is the pressure
`V` is the volume
`n` is the number of moles of amount of substance of gas
`R` is the ideal, or universal, gas constant.
`T` is the temperature of the gas

Since temperature is kept constant the RHS of the equation is a constant.
`=>PV="Constant"`

As such the graph of `PV` against `P` should be a straight line parallel to the `P` axis.

We can test this by plotting `PV` vs `P` of experimental values as shown below.

The computer gives the equation for the best fit line as

`PV= -0.149P + 6192.8`

This implies that the line starts at `PV = 6183.86` at the left hand end and finishes at `6163.0` at the right hand end.

Using only two significant figures for the `PV` product, it starts and ends at `6200`.

Therefore, within the limits of experimental error,

`PV = "constant"` → Boyle's Law