what is gas pressure?

Gas pressure is the force exerted by contained gas on a unit of the area of the envelope containing the gas molecules. Gas pressure P (force/unit area) equals nRT/V where n is moles of gas, T is the temperature in degrees, V is the volume in cubic units, and R is the gas constant in (force/unit area)(1/moles)(1/degrees)(cubic units of gas). The units on the right hand side of the equation cancel except for the force/unit area which provides the units of the pressure on the left side of the equation..

Gas molecules are in constant motion and their speed is dependent, in part, on how much room they have to move about. If the area containing the gas is reduced, they begin to bounce around faster and exert more force against the container. Pressure is a measurement of that force.

gas pressure is how much gas is pushing.