(4.4.2)--2.11-2Examplesofanisothermalbaro.pdf

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1、Examples of an isothermal barometric formula()(0)exp()(0)exp()mM gzmgzp zppkTRT()(0)exp()(0)exp()mMgzmgzn znnkTRTThe population density of gas molecules varies with heightIsothermal barometric formulaIt is experimentally measured that atmospheric pressure decreases by about 133.3 Pa for every 10 m r

2、ise at normal temperature,which is not too high from sea level.Try to isothermal barometric formula to verify the result(atmospheric pressure at sea level is calculated as 1.013105 Pa,and the temperature is 273K).mRTpzM g p 5310013.13.133101097.2827331.8m3.10SolveExample/00mM gz RTmgz kTpp ep e0dd()

3、mM gz RTmM g zpp eRT ddmM gpzpRT Isothermal barometric formulaIf we differentiate both sides of this equation,we getLhasa is about 3600 m above sea level with the temperature of 273 k.Lets ignore the temperature changes with height.When the pressure at sea level is 1.013105 Pa,By the isothermal baro

4、metric formula,we get329 109.8 36005(8.31 273)01.013 10mM gzRTpp eeSuppose the volume of inhaled air is V0 each time,and a person should breathe x times in Lhasa )17()(000VpxVp26.7x pa10645.05(1)the atmospheric pressure in Lhasa.(2)If someone is on the sea surface breathing 17 times per minute,how many times he needs to breathe in Lhasa to inhale the same mass of air.M=29 x 10-3 kg/molSolveExampleFindthen we haveThanks