I6-02
Experimentally determine the diameter of the nitrogen molecule and to determine the order of magnitude of the mean free path of nitrogen gas molecules at STP.

Using the pan balance pour 700 cm3 of liquid nitrogen and demonstrate that it has a mass of about 560 grams. The mass of the dewar is about 421 grams. For liquid nitrogen the volume per molecule can then be determined to be

Vol/Mol=700 cm3/[(560g)/(28g/mole)(1mole/6.0x1023molecules)]=5.8x10-23cm3.

Assume molecule is a cube, so d = 3.9x10-8 cm.

Volume per molecule @ STP = 22.4x103 cm3 / 6.0 x 1023 = 3.7x10-20 cm3

Mean free path = V/d2 = 3.7x10-20 cm3 / (3.9x10-8 cm)2 = 2x10-5 cm.
I6, I0, ME1

i6-02a