CHE 1301 Chapter Notes - Chapter 5: Barometer, Gas Laws, Inverse Relation
16 Dec 2017
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Pressure: force exerted per unit area by gas molecules as they strike the surfaces around them; result of molecular collisions. high concentration = greater pressure. Inhale: greater volume = low concentration = low pressure. Gas flow from high pressure to low pressure. low density = low pressure. Pressure = few gas particles = lower force per unit area = low pressure pressure decreases with increasing altitude. Unit of pressure: millimeter of mercury (mmhg) measured with a barometer: evacuated glass tube, the tip of which is submerged in a pool of mercury. Liquid mercury is forced upward into the evacuated tube by atmospheric pressure on the liquid"s surface. Mercury"s density convenient to measure pressure because of a column of hg. When atmospheric pressure rise, height of mercury column rises as well. 1 atm pushes a column of mercury to a height of 760mm, 1 atm=760mmhg. Si unit of pressure: pascal (pa) defined as 1 newton (n) per square meter.
