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Slide 2 Chapter 14 Gases Slide 3 The Gas Laws 1. Kinetic Theory a. Gas particles do not attract or repel each other each other b. Gas particles are much smaller than the distance between them the distance between them c. Gas particles are in constant random motion motion Slide 4 d. No kinetic energy is lost during collisions e. All gases have the same average kinetic energy at a given temperature Slide 5 2. Boyles Law P 1 V 1 = P 2 V 2 constant T and pressure is an absolute pressure Slide 6 3. Charless Law V 1 /T 1 = V 2 /T 2 constant P & T measured in Kelvin Slide 7 Plots of V vs. T (Different Gases) Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 407 Slide 8 4. Gay-Lussacs Law P1/T1 = P2/T2 constant V Slide 9 5. Combined Gas Law P 1 V 1 /T 1 = P 2 V 2 /T 2 Combined Gas Law Combined Gas Law 6. Avogadros Principle equal volumes of gases at the same temperature & pressure contain the same number of particles 7. Molar Volume the volume occupied by 1 mole of a gas at STP (standard temperature & pressure) = 22.4 L 8. STP = 0 O C & 1 atmosphere Slide 10 Molar Volume Timberlake, Chemistry 7 th Edition, page 268 Slide 11 The Ideal Gas Law 1. Ideal Gas behaves according to the Kinetic Theory and obeys the various gas laws (Boyles, etc) 2. Ideal Gas Law PV = NRT where n = the number of moles and R = ideal gas law constant 3. A lower temperature and higher pressure cause a gas to behave less like an ideal gas (real gas) Slide 12 4. The larger the gas molecule the less ideal the behavior 5. The more polar the gas molecule the less ideal the behavior Slide 13 Gas Stoichiometry