《化学专业英语》课件chapter4

1、Chapter 4 The Gaseous State4.1 the nature of Gases compressible, volatile, pressure and volume vary with temperature low densities and flow easily4.2 kinetic-molecular theory of gases the average kinetic energy: proportional only to the absolute temperature of the gas. At given temperature, the diff

2、erent molecules of gas has the same average elastic collisions: the collisions of gas with others are perfectly elastic, with no loss of energy ideal gas: having all of above properties real gas: 4.2 Volume, Pressure, and Temperature Relationships1. Variables and ProportionalityVariables: pressure,

3、volume, temperatureConstants: fixed value that can not change2. Volume versus Pressure: Boyles law3. Volume versus temperature: Charless law4. STP: standard temperature(273K) and pressure (1atm) the volume at STP: the volume at 273k, 1atm4.3 Mass, Molecular, and Molar Relationships1. Gay-Lussacs Law

4、 :equal volumes of gases, measured at the same temperature and pressure, contain equal numbers of molecules.2. Molar Volume : the volume of one mole of a substance at STP. molar volume for any real gases: equal to 22.4L3. Ideal Gas Law (Mass and Density) where R is the ideal gas constant: 8.314 J/(K

5、mol)4. Pressure in Gas Mixture: Daltons law precondition: the gases in the mixture do not react.Partial pressure of each gas in the mixtrue: equal to the pressure of a single gas occupying the whole space of the mixtrue.Partial volume: the volume of a single gas when its pressure is equal to that of

6、 the whole mixtrue.4.4 Behavior of Gas Molecules1. Effusion and Diffusion: Grahams Laws the rates of Effusion and Diffusion are inversely proportional to the square roots of the densities of gases. 2. Deviations from the Gas lawsreal gas: occupying a finite volume interacting each other Van der Waals equation:Deviations from re