CHEM 150 1nd Edition Chapter 6 : Properties of Gasses Lecture 17Outline of Last Lecture • Hess's Law• Enthalpy Change• Standard condition of pressure. Outline of Current Lecture • The gass Phase • The Kelvin scale (K)• Absolute Zero Current Lecture-There is one gas law: the Ideal Gas Law-All other gas laws are special cases of this one.PV=nRT or PV/nT=RR= 0.0820575 L.atm/mol.K =62.3637L.torr/mol.K-The Kelvin scale (K)The coldest possible temperature is -273.15EC. This is called absolute zero and is the basis of the Kelvin temperature scale. Absolute zero is 0.00 KX °C = (x+273.15) KQ: 62.03g of nitrogen gas is sealed in a rigid container with a volume of 17.60L. The temperature is 35.00°C . What is the pressure of the gas in atm.?A: P= nRT/V =2.213776mol x0.0820575 x30.81K/ 17.60 =3.181atm Q: A sample of carbon dioxide occupies 550.0 mL at 36.7°C and 683.2 torr. How many moles of CO2 are present?A: n =PV/RT =683.2 torr x0.5500L/ 62.3637L.torr/mol.k (36.7 +273.15)K =0.01945mol CO2Q: 2KCIO3(s) ----> 2KCI(s) + 3 O2(g)If 83.69g of potassium chlorate are heated and the reaction goes to completion, what volume of oxygen gas (at 22.0°C and 1.042 atm) is produced?A: V= nRT/P = 1.024574mol/ x 0.082057mol.K/L.atm x .295.15K /1.042atm = 23.8092L O2 gass are formed Q: What is the density of sulfur dioxide gas at STP?A: d= 1.000atm x64.07g/mol /0.0820575L.atm/mol.K =2.88g/LQ: A sample of a pure compound in the gas phase has a mass of 902.1 mg and occupies avolume of 339.9 mL at 83.51°C and 0.9105 atm. What is the molecular weight of the compound?A: n= pv/RT = 0.9105atm x 0.339L / (278.15 +83.5K) =0.010574762mol0.9021g/ 0.0105747622mol
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