Chemistry - Gas pressure and its uses.

Gas pressure and its uses
As we encountered earlier, gas pressure comes about due to collision of gas molecules with the walls of its container. Gas pressure is used in many industrial processes and was the driving force behind the industrial revolution.
Early in the last century steam was used to drive many industrial machinery.
Wood was burnt to heat the water molecules inside huge boilers. As the water molecules in the gaseous state increased in number and speed, due to the high temperature, pressure inside the boiler increased.
The highly pressurised steam was used to move pistons and do useful work.
Steam powered vessels provided new forms of transport which created a flourishing economy.
The atmosphere is composed of a mixture of gases. It exerts a pressure called atmospheric pressure. Often we are oblivious to its existence. The presence and force of atmospheric pressure can be dramatically demonstrated with the Imploding Can demonstration. The can pictured on the right was crushed by atmospheric pressure when a vacuum was created inside the can. Click to see a 120kb movie.
	High atmospheric pressure lowers the temperature at which liquids boil. In space where the atmospheric pressure is zero, body temperature is enough to boil the water in the blood. This can be demonstrated with a syringe, hot water from the tap and a rubber stopper as shown on the left. Click to see a 120kb movie.
Exercises Continue with the ideal gas and the kinetic theory of gases