Gases and their Pressure

Pressure is defined as force per unit area. Gas particles exert pressure when they collide with the walls of their container. Because there are so many particles, the pressure can be substantial. Pressure has many units. The standard in chemistry is the atmosphere (atm). One atmosphere is equivalent to 14.7 psi (pounds per square inch) is equal to 101.3 kiloPascals (kPa) is equal to 760 mmHg or 760 torr. This quiz will cover basic pressure concepts. Select the best answer from the given choices.

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At sea level, the average air pressure is 760 mmHg. How many kilopascals is this?

101.3 kPa

490 kPa

11.3 kPa

171.3 kPa

If you are standing on top of Mount Everest, is the air pressure higher or lower than the pressure at sea level?

Lower

Higher

At sea level, the average air pressure is 760 mmHg. How many kilopascals is this?

101.3 kPa

490 kPa

11.3 kPa

171.3 kPa

Dalton's law of partial pressures says that individual gases exert different pressures independently of each other when combined in a container. Ptotal = P1 + P2 + P3 + ...Pn A mixure of oxygen, carbon dioxide and nitrogen has a total pressure of .97 atm. What is the partial pressure of oxygen if the partial pressure of nitrogen is .12 atm and the partial pressure of carbon dioxide is .70 atm?

0.98 atm

0.12 atm

0.15 atm

1 atm

What is the partial pressure of hydrogen gas in a mixure of hydrogen and helium if the total pressure is 600 mmHg and the partial pressure of helium is 439 mmHg?

100 mmHg

90 mmHg

123 mmHg

161 mmHg

This is an example of the everyday application of pressure in: