Helium gas is collected over water at 25◦c. what is the partial pressure of the helium, given a barometric pressure of 720 mm hg? answer in units of mm hg.

The size (radius) of an oxygen molecule is about 2.0 ×10−10m. make a rough estimate of the pressure at which the finite volume of the molecules should cause noticeable deviations from ideal-gas behavior at ordinary temperatures (t= 300k ). assume that deviatons would be noticeable when volume of the gas per molecule equals the volume of the molecule itself.