The Kelvin temperature scale is used when describing gases. This is because the Kelvin scale is directly proportional to the kinetic energy of the gas particles. Thus, 0 K (absolute zero) means no kinetic energy. If particles have no kinetic energy, then they are not moving and cannot cause any pressure inside their container. This is why absolute zero (0 K) is also where pressure equals zero.
This temperature scale will become especially important when we begin gas calculations. Gas variable relationships we have explored can be expressed as mathematical equations. For example, as temperature decreases, so does volume, so if temperature is cut in half, volume will also be cut in half. This mathematical relationship will only hold true if the temperature is in Kelvin.
The Kelvin scale has no negative temperature as there can be no negative volumes, no negative pressures, and no negative number of particles.
The formulas to convert from the Celsius scale to Kelvin and back again are shown below. You will need them to complete the questions at the bottom of the page.
Celsius to Kelvin: K = oC + 273
Kelvin to Celsius: oC = K - 273
