:gases :properties :1.gases expand to fill the shape of the container. :2.they diffuse in one another and mix in all proportions. :3.they are invisible(there are no visible particles. :4.some are combustible some are inert. :4 properties determine the physical behavior of a gas. amount of the gas, volume, temperature,and pressure. :recall the pressure is the force per unit area d=f/a :Simple Gas Laws :Boyles law-gas volumes are inversly proportional to gas pressure :p1v1=p2v2 :Charles law-the volume of a fixed amount of gas at constant pressure is directly proportional to the kelvin temperature. :v1/t1=v2/t2 :Gay-Lussacs law-the pressure of a fixed amount of gas at constant volume is directly proportional to the kelvin temperature. :p1/t1=p2/t2 :combined gas law-combines each of the simple gas laws. :p1v1/t1=p2v2/t2 :STP Standard temperature and pressure. :pressure=1atm :volume=22.4L :temperature=273K :amount=1 mole. :Avogadros law-Equal volumes and equal numbers. :1.Equal volumes of different gas compared at the same temperature and pressure contain equal number of molecules. :2.at fixed temperature and pressure the volumes of a gas directly proportional to the amount of gas. :v1/n1=v2/n2 :Ideal Gas Law-PV=nRT R=.08206 :Application of the ideal gas law :molar mass: :PV=mRT/M m=actual M=molar mass :Gas density-d=MP/RT :Gas densities differ in 2 ways from solids and liquids. :1.gas densities depend strongly on pressure and temperature incresing as the gas pressure increases and decreases as the temperature increases.densities of liquids and solids also depend somewhat on temperature but depend far less on the pressure. :2.the density of a gas is diresctly proportional to its molar mass no simple relatiionship exists between density and molar mass for liquids and solids. :Daltons law of partial pressure :p1+p2+p3...=p(total) :Kinetic molecular theory of gas :1.a gas is composed of very large numbers of extremely small particles in constant,random,straight line motion. :2.molecules of a gas are seperated by great distances. the gas is mostly empty space. :3.molecules collide with one another and with the walls of their container. However, the collisions occur very rapidly and most of the time molecules are not colliding. :4.it is assumed that there are no forces between molecules except very breifly during collisions. molecules act independantly of all others and are unaffected by their presense. :5.individual molecules may gain or lose energy as a result of collisions. the total energy remains constant :Gas properties relating to the Kinetic molecular theory. :every gas molecule undergoes frequent collisions w/other gas molecules + as a result keep changing directions. gas molecules follow a zigzag path, which slows them down in getting from one point to another in a gas. still the net rate at which gas molecules more in particular direction depends on their average speed as a result of collisions. :Diffusion=migration of different substances as a result of random molecular motion. :Effusion=escape of gas molecules from their container. :Grahams law-the rate of effusion or diffusion of 2 different gases are inversely proportional to the square roots of their molar mass :n1/n2=§(M2/M1) :non ideal gases :how well a gas acts like an ideal is measured by a compressability factor,which is a ratio pv/nrt for an ideal gas this is equal to 1. :principally all gases behave ideally at sufficient low pressures below 1atm. :gases behave ideally at high temperature and low pressures. :gases behave non ideally at opposites. :intermolecular forces of attraction begin to take over with higher pressures. :an equation that deals w/real gases corrects for thevolumes associated w/molecules themselves and for intermolecular forces of attractionªª :van derwaals equation :(p+(n2a/v2))(v-nb)=nrt :v=volume :n=moles of gas :p=pressure :a+b=specific values of gas