Chapter 10 ap chemistry I. Characteristics of Gases air 78% Nitrogen

 Sana 31.01.2018 Hajmi 445 b. • expand to fill container spontaneously • Atmos. Pressure = 1x10^5 Pa or 1x10^2 kPa Measuring Atmospheric Pressure • = 101.325 kPa Robert Boyle (1627-1691) • The value of the constant depends on the temperature and amount of the gas Jacques Charles (1746-1823) • Increase the temp increase the vol Joseph-Gray-Lussac (1788-1823) Example • Using Lussas’s Law • Later it was found that at STP ( one atm and 0 deg C) one mole (6.02 x 10^23 molecules) of any gas occupies exactly 22.4 liters of that gas.  • Avogadro’s # = 22.4 l • A sample of KNO3 is heated producing O2 gas in a 750 ml flask under 2.8 atms of pressure. If the temperature is 53.6 deg C how many moles are produced? • P1V1/T1 = P2V2/T2 • If one liter of air at room temp 25 deg C and one atmos is compressed to a volume of 3.3 ml at a pressure of 1000 atm. What is the new temp of the sample? • Given D= mass/vol N = m (mass)/M (molar mass) • What is the density of carbon tetrachloride at 714 torr and 125 deg C? Gas Mixtures and Partial Pressures • At cons. temp and volume the total pressure of a gas sample is determined by the number of moles of a gas present – whether a single gas or a mixture. • A gaseous mixture made of 10g of oxygen and 10g of methane is placed in a 10 liter vessel at 25 deg c. What is the total pressure in the vessel? • Pt • A synethic atmosphere is created by blending 2 mol percent CO2, 20 mol percent O2 and 78 mol percent N2. If the total pressure is 750 torr calc the partial pressure of the oxygen component. Collecting Gas Over Water • Pressure of Water Table • How many grams of KClO3 were decomposed? • Molecules travel in random patterns in straight lines in all directions at various speed. Properties are same in all directions. • 5. The average Ke of a molecule is proportional to the absolute temperature. • Freq is inversely proportional to the gas volume Inc. vol decrease freq collisions • So if the average KE of a molecule of mass m and average speed mu is ½ mmu^2 then PV port to NT also postulate 5 and N is port to moles of gas then PV = nRT • Note the distribution of molecules at diff speeds is temp dep (called a maxwell distribution • Mu = • one direction • vol, average molecular speed • Calc. the ration of effusion rates of molecules of CO2 and SO2. Do'stlaringiz bilan baham:

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