Atmosphere (atm)

Definition

Atmosphere (atm) is a unit of pressure defined as 101,325 Pa. It represents the average pressure exerted by Earth's atmosphere at sea level.

5 Must Know Facts For Your Next Test

1. 1 atm is equivalent to 760 mmHg or 760 torr.
2. Standard Temperature and Pressure (STP) conditions are defined as 0°C and 1 atm.
3. Boyle's Law states that the pressure of a gas is inversely proportional to its volume at constant temperature.
4. The Ideal Gas Law can be expressed as PV = nRT, where P is in atm when using R = 0.0821 L·atm/(K·mol).
5. Dalton's Law of Partial Pressures states that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of individual gases.

Review Questions

Related terms

Pascal (Pa): A unit of pressure equal to one newton per square meter.

Torr:

A unit of pressure where one torr is equal to one millimeter of mercury (mmHg).

Ideal Gas Law:

$$PV = nRT$$, an equation relating the pressure, volume, amount, and temperature of an ideal gas.