State the basic differences between a gas and a vapor.

Hint: At room temperature, vapors are in solid or liquid state while a gas is just a gas. A phase change has occurred in the case of vapor while it is not there in gas. A gas is a state of matter whereas a vapor is not. Vapor is a transitional phase from liquid to gas. A vapor can be converted to liquid by increasing pressure or decreasing temperature. Critical temperature is the maximum temperature at which liquid exists. It can exist in solid or liquid state below the critical temperature.

Complete step by step solution:
Matter is something that is occupied by space and mass. There are three states of matter- solid, liquid and gas. Matter is made up of elements. These elements have their own physical and chemical properties.
Vapor is not a state of matter, but it is a phase where it can exist in either solid or liquid state at room temperature. While gas has only one substance at normal condition i.e. room temperature. At a specific temperature it converts to solid or liquid state. Generally, a vapor is formed by evaporation. Evaporation is a process of boiling a liquid. We all have seen the water vapor on the lid of the vessel while water is boiled.

Additional information:
- A gas consists of a single state i.e. gas in normal condition. While vapor is a combination of liquid and gaseous state at room temperature.
- Vapor undergoes a phase change from liquid to vapor. But gases when undergone phase change, it will be changed to either solid or liquid.

Note: It is surprising to know that earth’s atmosphere contains a greater amount of water vapor than greenhouse gases. Measuring the water vapor content is very difficult. It is familiar that the cause of cloud formation is vapor formation due to condensation. Vapor may coexist with liquid or solid.