TOPIC:

ID Code: I6-02
Purpose: 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.
Description: 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.

Availability: Available