Gaseous State

                   Gaseous State 

                    In the gas state, the molecules are located far away from each other. Hence there are very week attraction forces between them. The motion of the molecule can stopped by the walls of the vessel, so these molecules can take up the entire space of the vessel. Gases have many similar properties for this reason. These properties are unaffected by the nature of gases.

(1.)     Expansion and Compressibility-

                Gaseous molecules moves freely in straight lines and this motion can be stopped by the walls of the vessel. Therefore, the larger the vessel, the larger the gas will be spread in the same size, similarly due to the large space between the gases. The gases molecules can came very close by increasing the pressure.  

(2.)    Low Density-

                 Due to the low molecules force between gases, there is a lot of free space between gases them, So they are very low in density (1000 times less than solid and liquid). Its unit is expressed in grams/ liter

(3.)    Homogeniety-

                 Gases due to diffusion properties, when there is more then one gas, they would spread over the entire area to form a homogeneous mixture.

(4.)    Liquefaction-

                        Gases can be liquefied at low temperature and high pressure, but this temperature must be less then the critical temperature. Critical temperature no matter on increased gases can not be liquified.

(5.)     Measurable properties of laboratory-

(i.)       Mass:

                      The mass of a gas can be measured by the difference between the weight of empty container and the gas filled container.     

(ii.)         Volume:

                       The volume of the vessel in the volume of the gas.

(iii.)        Pressure:

                       The force exerted on the unit area of the walls due to the collision on the walls of the vessel is called pressure. We measure is with a barometer. 

                             P = Force / Area

(iv.)        Temperature:

                        Temperature can be measured by thermometer. Its unit is Kelvin. The temperature of a gas is measure of their Kinetic energy.

                                       

                            Molecular Motion in Gas

                 

                          In the gaseous are three type of motion, vibration, rotation and transfer of molecules. The smell of any substance is spread from one corner to another due to molecular motion of gases.

                                      

                             Ideal and Real Gases

                            Ideal gases follow gas rules (Boyle, Charles, Galusek, Avogadro) whereas real gases follow these rules only to some extent at low pressure and high temperature.