Pull the plunger out until the reading is 20 cm3. Read the pressure at this value of V.
Read the value for pressure at each new value of V, as the volume is decreased from
20 cm3, in steps of 1 cm3, down to 5 cm3. Note that since the volume is 10 cm3 at
atmospheric pressure, you will have to exert some force to pull the plunger out from
10 to 20 cm3, and to push it in from 10 to 5 cm3. Put both hands on the syringe when
you do this, not one hand on the syringe, and one hand on the pressure sensor, as this
may damage the connector. Make a plot of p versus 1/V. Determine the number of
moles for the air used in this process.