1. Nature of Gases (and liquids and solids)

2. Kinetic-Molecular Theory Assumptions  Size: gases are tiny particles separated by empty space; they do not attract or repel each other  Motion: gas particles are in constant, random motion  Energy: collisions between particles are elastic (no energy is lost)  Size: gases are tiny particles separated by empty space; they do not attract or repel each other  Motion: gas particles are in constant, random motion  Energy: collisions between particles are elastic (no energy is lost)

3. Pressure Units (you don’t have to copy this, but you do need to recognize which units are for pressure!) These are conversion factors! STOP & THINK: How many atmospheres do you have if you have 50.65 kilopascals? Soda Air Pressure

4. http://www.youtub e.com/watch?v=t- Iz414g- ro&feature=relate d

5. Energy in Gases  Temperature (in Kelvin) is the measure of the amount of energy in a gas sample.  Average kinetic energy is proportional to Kelvin temperature.  All samples at the same temperature have the same average kinetic energy.  Kelvin = °Celsius + 273  Temperature (in Kelvin) is the measure of the amount of energy in a gas sample.  Average kinetic energy is proportional to Kelvin temperature.  All samples at the same temperature have the same average kinetic energy.  Kelvin = °Celsius + 273

6. sToP & tHinK  You have two samples of gas at 22 C, one is hydrogen and one is oxygen.  What is the temperature in Kelvin?  How do their kinetic energies compare?  You have two samples of gas at 22 C, one is hydrogen and one is oxygen.  What is the temperature in Kelvin?  How do their kinetic energies compare? http://www.youtube.com/watch?v=UNn_trajMFo

7. What about liquids? (don’t copy)  More attractive force between particles than for gases  Particles can flow past each other  Relationship between temperature and kinetic energy still applies!  More attractive force between particles than for gases  Particles can flow past each other  Relationship between temperature and kinetic energy still applies!

8. What about solids? (don’t copy)  More attractive force between particles than for gases and liquids  Particles vibrate around a point… no flow, fixed locations  Different crystalline and non-crystalline forms depending on the atoms present  Relationship between temperature and kinetic energy still applies!  More attractive force between particles than for gases and liquids  Particles vibrate around a point… no flow, fixed locations  Different crystalline and non-crystalline forms depending on the atoms present  Relationship between temperature and kinetic energy still applies!

9. Phase Changes  Require Energy:  melting: s --> l  vaporization: l --> g  sublimation: s --> g  Release Energy:  condensation: g --> l  deposition: g --> s  freezing: l --> s  Require Energy:  melting: s --> l  vaporization: l --> g  sublimation: s --> g  Release Energy:  condensation: g --> l  deposition: g --> s  freezing: l --> s

10. Phase Diagrams  show the phase a substance will be at a specific pressure (P) and temperature (T)  Triple point: P & T at which all three states of matter will be present  show the phase a substance will be at a specific pressure (P) and temperature (T)  Triple point: P & T at which all three states of matter will be present http://web.visionlearning.com/custom/chemistry/ animations/CHE1.1-an- threestates.shtml

12. Vaporization - how sweat cools your body  Fastest moving particles go from liquid to gas phase  Overall kinetic energy of liquid phase drops, so temperature drops  Energy is required to give particles the velocity to change phase - that energy comes from your body heat. ^ a close up of your sweaty armpit

13. Diffusion  movement from high to low concentration  caused by random collisions in which no energy is lost  rate of diffusion depends on temperature (amt of KE) and the mass of the particles  movement from high to low concentration  caused by random collisions in which no energy is lost  rate of diffusion depends on temperature (amt of KE) and the mass of the particles air sprays salt in beaker dye in beaker…

14. Dalton’s Law of Partial Pressures  At a specific temperature and pressure, the ‘partial’ pressure of one mole of gas is the same regardless of the gas identity.  In a gas mixture, the total pressure equals the sum of the pressure of each gas.  P total = P 1 + P 2 + P 3 + …. P n  At a specific temperature and pressure, the ‘partial’ pressure of one mole of gas is the same regardless of the gas identity.  In a gas mixture, the total pressure equals the sum of the pressure of each gas.  P total = P 1 + P 2 + P 3 + …. P n

15. sToP & tHinK  You are asked to add chlorine to your neighbor’s swimming pool and spa while they’re out of town. In which one will the chlorine totally spread out in the liquid faster?  Use the assumptions from kinetic molecular theory to explain!  A sample of gas has a total pressure of 5 atm. It contains argon and one unknown gas. The argon contributes 3.5 atm of pressure. What is the pressure of the unknown gas?  Can we use this information to figure out the identity of the gas?!?!  You are asked to add chlorine to your neighbor’s swimming pool and spa while they’re out of town. In which one will the chlorine totally spread out in the liquid faster?  Use the assumptions from kinetic molecular theory to explain!  A sample of gas has a total pressure of 5 atm. It contains argon and one unknown gas. The argon contributes 3.5 atm of pressure. What is the pressure of the unknown gas?  Can we use this information to figure out the identity of the gas?!?!