Presentation on theme: "Gas Laws Robert Boyle Jacques Charles Amadeo Avogadro"— Presentation transcript:
1 Gas Laws Robert Boyle Jacques Charles Amadeo Avogadro Joseph Louis Gay-Lussac
2 The Combined Gas LawThe combined gas law expresses the relationship between pressure, volume and temperature of a fixed amount of gas.
3 Boyle’s LawPressure is inversely proportional to volume when temperature is held constant.
4 Charles’s LawThe volume of a gas is directly proportional to temperature, and extrapolates to zero at zero Kelvin.(P = constant)Temperature MUST be in KELVINS!
5 Gay Lussac’s Law The pressure and temperature of a gas are directly related, provided that the volumeremains constant.Temperature MUST be in KELVINS!
6 Avogadro’s LawFor a gas at constant temperature and pressure, the volume is directly proportional to the number of moles of gas (at low pressures).V = ana = proportionality constantV = volume of the gasn = number of moles of gas
7 PV = nRT Ideal Gas Law P = pressure in atm V = volume in liters n = molesR = proportionality constant= L atm/ mol·KT = temperature in KelvinsHolds closely at P < 1 atm
8 Real Gases Pideal Videal At high pressure (smaller volume) and low temperature (attractive forces become important) you must adjust for non-ideal gas behavior using van der Waal’s equation.corrected pressurecorrected volumePidealVideal
10 Density and the Ideal Gas Law Combining the formula for density with the Ideal Gas law, substituting and rearranging algebraically:M = Molar MassP = PressureR = Gas ConstantT = Temperature in Kelvins
11 Gas Stoichiometry #1If reactants and products are at the same conditions of temperature and pressure, then mole ratios of gases are also volume ratios.3 H2(g) N2(g) NH3(g)3 moles H mole N moles NH33 liters H liter N liters NH3
12 Gas Stoichiometry #2 3 H2(g) + N2(g) 2NH3(g) How many liters of ammonia can be produced when 12 liters of hydrogen react with an excess of nitrogen?3 H2(g) + N2(g) 2NH3(g)12 L H22L NH3= L NH38.03L H2
13 Gas Stoichiometry #3How many liters of oxygen gas, at STP, can be collected from the complete decomposition of 50.0 grams of potassium chlorate?2 KClO3(s) 2 KCl(s) + 3 O2(g)50.0 g KClO31 mol KClO33 mol O222.4 L O2g KClO32 mol KClO31 mol O2= 13.7 L O2
14 Gas Stoichiometry #4How many liters of oxygen gas, at 37.0C and atmospheres, can be collected from the complete decomposition of 50.0 grams of potassium chlorate?2 KClO3(s) 2 KCl(s) + 3 O2(g)50.0 g KClO31 mol KClO33 mol O20.612=mol O2g KClO32 mol KClO3= 16.7 L
15 Dalton’s Law of Partial Pressures For a mixture of gases in a container,PTotal = P1 + P2 + PThis is particularly useful in calculating the pressure of gases collected over water.