Pressure - a measure of the ratio of the force acting perpendicular to the surface to the area of this surface.
distinguishing feature of gas is its ability to fill the entire vessel or a vessel within a limited space.That is a vessel filled with gas uniformly.As the filling gas pressure on the vessel wall.If you do not go into the structural analysis of the gas, we can say that the gas pressure is balanced across the vessel.But, given the molecular structure of the gas can not speak about its quiescent state.The molecules are always in motion and hit the wall, facing each other.At one point, these impacts may be more intense, and in the other - even absent.This chaotic movement of molecules.
faced with an obstacle, the molecule affects him with a force equal to the mass of the molecule on its speed.Based on the walls, a molecule of double this figure.This result should be multiplied by the number of beats per second per one square centimeter.The resulting record according to Newton's law is valid, which affects this area, multiplied by the duration.The resulting value is the pressure of the gas mixture.
What factors determine the pressure of the gas?
most important is for the compression of gases.In other words, the number of molecules which are located in this vessel.An example is the process of inflating the tires.
second indicator - is the temperature of the gas mixture.The pressure can vary under the influence of two factors at the same time: a change in temperature or change in volume.But each of these indicators has a negligible impact on the parameters of the other factor.The optimum gas pressure, i.e. its equilibrium occurs when balanced temperature and mechanical impact.
When the gas pressure in the whole container becomes uniform, comes the mechanical balance.At this point, it stops the movement in different parts of the gas mixture.Thermal equilibrium is observed when the temperature becomes the same for different parts of the tank and heat exchange occurs between the parts of the gas.
From all this it can be concluded that the gas pressure is determined by the movement of molecules and their impacts on the vessel wall.If reducing the amount of gas in the vessel, the pressure will increase.Conversely, when the amount of gas in the pressure vessel decrease.This rule is effective at constant rates of temperature and mass of the gas.
As the temperature increases, an increase of gas pressure.This occurs only at constant rates of gas mass.
gas pressure measurement occurs without the use of formula.It is necessary for practical training and experience.For measuring the air pressure is only required outside atmospheric pressure.To measure the gas pressure in the sealed container, it requires some auxiliary instruments: barometer, thermometer, scales, pressure gauge.
air is also a mixture of gases.To measure air pressure, you can use an ordinary aneroid.On his scale using units such as the atmosphere or millimeters of mercury.You can also use a mercury barometer, which is less convenient, but more accurate.
To measure the pressure in the closed container, generally use a pressure gauge.For more accurate measurements use the electronic pressure gauge, which you can configure the measuring range.
If you know the basic characteristics of the gas, we can use the formula to calculate its pressure.
