Gases conform to the volume of the container in which they are confined and are easily compressible. The pressure exerted by a gas on its container is defined as the number of collisions per unit area between the molecules of the gas and the container wall. When measuring properties of gases, a common environment is standard temperature and pressure (STP). Standard temperature is 273.15 Kelvin. Standard pressure is 1 atmosphere. Although temperatures are often measured in degrees Celsius, the calculations should be performed with Kelvin measurements. Note that Kelvin measurements are not referred to as 'degrees Kelvin' but just as 'Kelvin.' Other units for pressure include the Torr, millimeters mercury, and inches mercury:
Calculations should be performed with atmospheres.
