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Part A. Address the following Introduction to Psvchrometric questions and calculations. 1. Dry air is mostly made up of two gases, namely nitrogen and oxygen with mole fraction percent's being 79%(0.79) and 21%(0.21), respectively (there are small amounts other gases like Ar and CO2, which are lumped in with nitrogen). What's the molecular weight of gaseous nitrogen (Mn) and oxygen (Mo) (noting that M has units of lbm/lbmolorkg/kgmol )? Does a dry-air molecular weight of Ma=28.97lbma/lbmola ("a" stands for dryair) seem reasonable? Calculate "Ma", weighting the two molecular weights by the above mole fraction percents. Compare your answer to that given above by calculating % difference. Calculation: Note: from here on out, erase nitrogen and oxygen from your memory, as when it comes to psychrometrics, there is only one gas mixed with "water vapor" and that gas is "air" 2. Moist Air--What is the molecular weight of water vapor, Mv= lbmv/lbmolv (" v " stands for water vapor)? The focus of HVAC is on ideal gas mixtures of dry air and water vapor, called "moist air" (all air has water vapor in it, unless we are talking about a 5 gram sample of dry air in a test tube in a government lab somewhere in the Rocky Mountains - so they say?)