People find it difficult to differentiate it between the gas and vapor as the latter is also a kind of the gas, and it is not labeled as any other separate state of matter. The gas is the state of matter which has the least intermolecular attraction between its molecules and is invisible to the naked eye. Contrary to this, the vapor is the equilibrium state between the gases and liquid, which can bounce back to its original form, liquid after the pressure is exerted on it and the temperature is kept constant. Here it should be noted that the gaseous material we get in from the liquids at the equilibrium state is known as the vapor. The gaseous material we get from the water (liquid) is known as water vapor, not as the water gas.
What is Gas?
The gas is classified as one of the four states of matter; they have distinct feature of occupying the available space regardless of the shape and volume. This feature is because of the presence of very little intermolecular attraction between the molecules. The other three states of matter are solid, liquid and plasma. The solids have fixed shape and the volume, whereas the liquids have fixed volume but lack the fix shape feature; they take the shape of the container they are poured in. The gaseous molecules are constantly moving independently due to the weak force of attraction present between the molecules. The gas can fill out the container of any of the size as the gaseous molecules are constantly on the move. The compounds which even remain in the gaseous state are classified as the gas. For example, the Carbon dioxide is classified as gas, that is because it remains gas even in the room temperature, or in any other words, we can say that CO2 never changes its state of matter. Therefore, you will never hear the term Carbon dioxide vapor; it is always referred as a carbon dioxide gas.
What is Vapor?
The vapor is a type of gas that is in the equilibrium state in between the gas and water; it can bounce back into its original liquid state if the pressure is applied on it and the temperature is kept constant. The original state of the vapor can also be solid, so the vapor in its neutral phase at the room temperature should either be liquid or the solid. The vapors are more easily compressible as compared to the gases as they are constantly under the transition. When vapor has to move back to its original state, it is required that the pressure should be exerted on it and the change in temperature is not required. The vapor is the term used for the gaseous molecule that can either be the liquid at the room temperature. The water evaporated from the water is described as the water vapor, and when the pressure is exerted by the water vapor, it turns back into the liquid state. In other words, water vapor is the water present in the gaseous state. The vapors are visible to the naked eyes as the physical change takes place in it.
Gas vs. Vapor
- The gas is one of the four states of matter, whereas vapor is a gaseous state where it is in the equilibrium state in between the gas and the liquid.
- The gas would not change its state at the room temperature or the neutral state. Contrary to this, at room temperature, the vapor get back to its original state that is either liquid or the solid.
- The change in temperature and pressure is necessary in order to change the phase of the gas. On the other hand, change in pressure is required for bringing back the vapor to the original state.
- The gas cannot be seen by the naked eye, whereas vapors are visible to the naked eye as they are under the constant transition.