Gases & Gas Laws
MEMORIZE!
1 atm
760 mmHg
760 torr
101.3 kPa (kilopascals)
14.7 psi
Atmospheric Pressure (atm) is the force exerted by gases in the Earth’s atmosphere.
Pressure is the force per unit area resulting from gas molecules colliding with each other and the
walls of their container.
A barometer measures atmospheric pressure (in mmHg).
A manometer measures the pressure of a specific gas.
As altitude increases, the air becomes thinner, resulting in less pressure exerted by gases on the
Earth’s surface: ATM ⇧ ALTITUDE ⇩
STP (Standard Temperature and Pressure) is defined as 1 atm and 0 °C.
Absolute zero is 0K = -273 °C, where the temperature is so low that particle motion stops,
meaning the gas has no average kinetic energy.
Properties of General Gases
Gases can fill any container.
Gases are easily compressed.
Gases mix completely with each other.
Gases exert pressure on their surroundings.
Gases and Kinetic Molecular Theory (KMT) - this theory models the behavior of gases
accurately, though approximations may not always hold true. It also explains the properties of an
ideal gas.
Ideal Gas Properties
Gas particles have no measurable volume or are very spread out. [NOT ALWAYS TRUE]
No intermolecular forces exist between gas particles. [NOT ALWAYS TRUE]
Gas particles have elastic collisions, meaning they don’t lose kinetic energy upon
collision and are always in constant, random motion.
MEMORIZE!
1 atm
760 mmHg
760 torr
101.3 kPa (kilopascals)
14.7 psi
Atmospheric Pressure (atm) is the force exerted by gases in the Earth’s atmosphere.
Pressure is the force per unit area resulting from gas molecules colliding with each other and the
walls of their container.
A barometer measures atmospheric pressure (in mmHg).
A manometer measures the pressure of a specific gas.
As altitude increases, the air becomes thinner, resulting in less pressure exerted by gases on the
Earth’s surface: ATM ⇧ ALTITUDE ⇩
STP (Standard Temperature and Pressure) is defined as 1 atm and 0 °C.
Absolute zero is 0K = -273 °C, where the temperature is so low that particle motion stops,
meaning the gas has no average kinetic energy.
Properties of General Gases
Gases can fill any container.
Gases are easily compressed.
Gases mix completely with each other.
Gases exert pressure on their surroundings.
Gases and Kinetic Molecular Theory (KMT) - this theory models the behavior of gases
accurately, though approximations may not always hold true. It also explains the properties of an
ideal gas.
Ideal Gas Properties
Gas particles have no measurable volume or are very spread out. [NOT ALWAYS TRUE]
No intermolecular forces exist between gas particles. [NOT ALWAYS TRUE]
Gas particles have elastic collisions, meaning they don’t lose kinetic energy upon
collision and are always in constant, random motion.
