CHEM 302 Chapter Notes - Chapter 2: Molecular Diffusion, Net Force, Ideal Gas Law

• School: UBC
• Department: Chemistry
• Course: CHEM 302
• Professor: Michael Wheeler

Document Summary

The atmospheric pressure is the weight exerted by the overhead atmosphere on a unit area of surface. It can be measured with a mercury barometer, consisting of a long glass tube full of mercury inverted over a pool of mercury: vacuum h. When the tube is inverted over the pool, mercury flows out of the tube, creating a vacuum in the head space, and stabilizes at an equilibrium height h over the surface of the pool. This equilibrium requires that the pressure exerted on the mercury at two points on the horizontal surface of the pool, a (inside the tube) and b (outside the tube), be equal. The pressure pa at point a is that of the mercury column overhead, while the pressure pb at point b is that of the atmosphere overhead. Hggh (2. 1) where r hg = 13. 6 g cm-3 is the density of mercury and g = 9. 8 m s-2 is the acceleration of gravity.