Vapor and Gas: Vapor is simply defined as the phase of a gas at a temperature where the same substance can exist in both liquid and solid states. Knowing how to calculate Vapor by using the Vapor pressure calculator can be incredibly useful.
Gas refers to a substance that has a single defined thermodynamic state at room temperature whereas a vapor refers to a substance that is a mixture of two phases at room temperature, namely gaseous and liquid phase.
Vapor and Gas
Gas is a substance whose molecules are in constant free motion past each other and can be compressed, which can also be referred to as a compressible fluid. When no liquid or solid can form at the temperature of the gas it is called a fixed gas.
However, it is significant to note that amongst the four states of matter there is a ‘gas phase’ which does not necessarily refer to gas as a distinct element but rather represents differences in interrelationships of molecules. Gas has its single gas particles vastly separated, making a gas invisible to the eye.
When a substance is at a temperature below its critical temperature it is in a ‘gas phase’ and therefore will be a vapor. A vapor can co-exist with a liquid or solid when they are in an equilibrium state.
Therefore from this, we can infer that vapor is a gas state of a substance at a temperature where it can co-exist with its liquid or solid state so for a liquid or solid to become vapor it does not have to first boil.
It is also of paramount importance to note that vapor is a result of the two types of vaporization of a liquid which are boiling and evaporation, the transition from the liquid phase to the ‘gas phase’.
Evaporation occurs at the surface of the liquid when its temperature is below the boiling temperature at a given pressure. Boiling occurs below the surface of the liquid.
Notable Distinctions Between Vapor and Gas
1. Vapor is a mixture of two or more different phases at room temperature; these phases are liquid and gaseous phases.
2. Gas usually contains a single thermodynamic state at room temperature.
3. Vapour has a definite shape of the gaseous particles when observed under a microscope. However, gas does not a definite shape when it is observed under a microscope.
4. Gases are a state of matter while vapor isn’t.
5. Generally, vapor consists of random molecules and atoms moving randomly about.
6. Gases are usually formed above its critical temperature, but below critical pressure.