Popular in General Chemistry
Popular in Chemistry
This 3 page Class Notes was uploaded by Caitrín Hall on Thursday April 28, 2016. The Class Notes belongs to CHEM 1127Q 001 at University of Connecticut taught by Fatma Selampinar (TC), Joseph Depasquale (PI) in Spring 2016. Since its upload, it has received 15 views. For similar materials see General Chemistry in Chemistry at University of Connecticut.
Reviews for Gases
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 04/28/16
Chapter 9 9.1 Gas Pressure Pressure – the force exerted on a given area P = F/A o Directly proportional to force and inversely proportional to area o The SI unit is the pascal (Pa); 1 Pa = 1 N/m 2 o 1 kPa = 1000 Pa; 1 bar = 100,000 Pa o In the U.S., pressure is measured in pounds per square inch (psi) o Atmosphere (atm) – originally represented the average sea level air pressure at the approximate latitude of Paris (45 degrees) o 101.3 atm = 101,325 Pa = 760 mm Hg = 760 torr = 14.7 psi o Barometer –the atmosphere exerts pressure on the liquid outside the test tube the column of liquid exerts pressure inside the tube the pressure at the liquid surface is the same inside and outside the tube; the height of the liquid in the tube is proportional to the pressure exerted by the atmosphere o Manometer – a device similar to a barometer used to measure the pressure of a gas trapped in a container 9.2 Relating Pressure, Volume, Amount, and Temperature: The Ideal Gas Law Pressure and Temperature: Amonton’s or Gay-Lussac’s Law Directly proportional at constant volume P1/T1 = P2/T2 Volume and Temperature: Charles’s Law Directly proportional at constant pressure V1/T1 = V2/T2 Volume and Pressure: Boyle’s Law Inversely proportional at constant temperature The graph of P vs. V is a parabola The graph of 1/P vs. V is linear P1 x V1 = P2 x V2 Moles of a Gas and Volume: Avogadro’s Law Directly proportional at constant pressure and temperature V1/n1 = V2/n2 The Ideal Gas Law = PV = nRT -1 -1 R is the ideal gas constant = 0.08206 L atm mol K and 8.314 kPa L mol K1 -1 An idea gas is a hypothetical construct that may be used along with kinetic molecular theory to effectively explain the gas If moles of an ideal gas are kept constant: (P1 V1)/T1 = (P2 V2)/T2 Standard Conditions of Temperature and Pressure STP = 273.15 K and 1 atm Standard molar volume = 22.4 L 9.3 Stoichiometry of Gaseous Substances, Mixtures, and Reactions Density of a Gas Mass to volume ratio Molar Mass of a Gas Grams per mole of a substance Combined with the molar mass equation: M = (mRT)/(PV) The Pressure of a Mixture of Gases: Dalton’s Law Dalton’s law of partial pressures: The total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the component gases The partial pressure of gas A is related to the total pressure of the gas mixture via its mole fraction (X) – a unit of concentration defined as the number of moles of a component of a solution divided by the total number of moles of all components P AX ×A Totalwhere X =An A/n Total Collection of Gases over Water Simple way to collect gasses that do not react with water: capture the gas in a bottle filled with water and inverted into a dish filled with water The pressure of the gas in the bottle can be made to equal the air pressure by raising/lowering the bottle When the water level is the same inside and outside the bottle, the pressure of the gas is equal to the atmospheric pressure The pressure of the pure gas is equal to the total pressure minus the pressure of the water vapor; vapor pressure of water – pressure exerted by water in EQ with liquid water in a closed container; depends on temperature Chemical Stoichiometry and Gases Avogadro’s Law Revisited Gases combine, or react, in definite and simple proportions by volume, provided all gas volumes are measured at the same temperature and pressure