Introduction>Fundamental ConceptsA mixture consists of two or more chemical constituents (species), and theamount of any species i may be quantified in terms of its mass density p; (kg/m?)or its molar concentration C, (kmol/m3). The mass density and molarconcentration are related through the species molecular weight, P; (kg/kmol),such thatP;= M,C,With p, representing the mass of species i per unit volume of the mixture, themixturemassdensityisp=ZpiSimilarly,the total number of molesper unit volume of the mixture isC=ZC,1
Introduction ➢Fundamental Concepts A mixture consists of two or more chemical constituents (species), and the amount of any species i may be quantified in terms of its mass density ρi (kg/m3 ) or its molar concentration Ci (kmol/m3 ). The mass density and molar concentration are related through the species molecular weight, ρi (kg/kmol), such that With ρi representing the mass of species i per unit volume of the mixture, the mixture mass density is Similarly, the total number of moles per unit volume of the mixture is
Introduction>Fundamental ConceptsThe amount of species i in a mixture may also be quantified in terms of its massfractionPim;poritsmolefractionCX,=CThus,≥ m,= 11Similarly, the total number of moles per unit volume of the mixture isZx= 1
Introduction ➢Fundamental Concepts The amount of species i in a mixture may also be quantified in terms of its mass fraction Thus, Similarly, the total number of moles per unit volume of the mixture is or its mole fraction
Introduction>Fundamental ConceptsFor a mixture of ideal gases, the mass density and molar concentration of anyconstituent are related to the partial pressure of the constituent through the idealgas law. That is,PiPiRTandPiRTwhere R, is the gas constant for species i and R is the universal gas constantUsing Dalton's law of partial pressures,p=ZpiandCiPiXcp
Introduction ➢Fundamental Concepts For a mixture of ideal gases, the mass density and molar concentration of any constituent are related to the partial pressure of the constituent through the ideal gas law. That is, where Ri is the gas constant for species i and R is the universal gas constant. Using Dalton’s law of partial pressures, and and
Introduction>Example Concentration of Individual Gases inAirConsider an air-water vapor mixture at a total pressure of 1 atm and a temperatureof 60C having 20% water vapor, 17% oxygen, and 63% nitrogen. Thepercentages refer to the ratio of partial pressures to total pressure. For simplicity,we are ignoring the other constituent gases in air. Calculate the molar and massconcentrations of each of the three gases in air.Schematic and givendatas1. Pvapor = 0.2 atm, Poxygen = 0.17 atm, Pnitrogen = 0.63 atm2.P=1atm3. T=333K4.Rg=8.315kJ/kmol.K
Introduction ➢Example Concentration of Individual Gases in Air Consider an air-water vapor mixture at a total pressure of 1 atm and a temperature of 60◦C having 20% water vapor, 17% oxygen, and 63% nitrogen. The percentages refer to the ratio of partial pressures to total pressure. For simplicity, we are ignoring the other constituent gases in air. Calculate the molar and mass concentrations of each of the three gases in air
Introduction>Example Concentration of Individual Gases in AirKnown: Fractions of individual gases in a mixtureFind:The molar and mass concentrationsAssumptions:Airbehaves as an ideal gasAnalysis:theconcentrationsarecalculatedas0.2 × 1.013 × 105 N/m2molPvapor7.32Cuaporm3R,T8.315J/mol.K×333K0.17 × 1.013 × 105 N/m26.22 mol PoxygenCoxygenm3RgT8.315J/mol.K × 333 K0.63 × 1.013 × 105 N/m2molPnitrogen23.0Cnitrogenm3RgT8.315J/mol.K×333K
Introduction ➢Example Concentration of Individual Gases in Air