Chapter 6 Gases 6.2 Gas Pressure

Gas Pressure Gas pressure is a force acting on a specific area Pressure (P) = force area has units of atm, mmHg, torr, lb/in.2, or kilopascals (kPa) 1 atm = 760 mmHg (exact) 1 atm = 760 torr 1 atm = 14.7 lb/in.2 1 atm = 101 325 Pa 1 atm = 101.325 kPa

Altitude and Atmospheric Pressure

Learning Check 1. What is 475 mmHg expressed in atm? A. 475 atm B. 0.625 atm C. 3.61  105 atm 2. The pressure in a tire is 2.00 atm. What is this pressure in mmHg? A. 2.00 mmHg B. 1520 mmHg C. 22 300 mmHg

Solution 1. What is 475 mmHg expressed in atm? The answer is B, 0.625 atm. 475 mmHg  1 atm = 0.625 atm 760 mmHg 2. The pressure in a tire is 2.00 atm. What is this pressure in mmHg? The answer is B, 1520 mmHg. 2.00 atm  760 mmHg = 1520 mmHg 1 atm

Barometer Measures Pressure A barometer measures the pressure exerted by the gases in the atmosphere indicates atmospheric pressure as the height in mm of the mercury column 760 mmHg = 1 atm

Atmospheric Pressure Atmospheric pressure is the pressure exerted by a column of air from the top of the atmosphere to the surface of Earth decreases as altitude increases is 1 atm at sea level is higher on rainy day

Learning Check 1. The downward pressure of the Hg in a barometer is _____ the pressure of the atmosphere. A. greater than B. less than C. the same as 2. A water barometer is 13.6 times taller than a Hg barometer (dHg = 13.6 g/mL) because A. H2O is less dense than mercury B. H2O is heavier than mercury C. air is more dense than H2O

Solution 1. The downward pressure of the Hg in a barometer is _____ the pressure of the atmosphere. The answer is C, the same as. 2. A water barometer is 13.6 times taller than a Hg barometer (dHg = 13.6 g/mL) because The answer is A, H2O is less dense than mercury.