Review Table A: STP 1 atm = 101.3 kPa = 760.0 mm Hg Vapor = gas that is usually a liquid Vapor Pressure: when a gas exerts pressure on its surroundings. SLG (endothermic) SL melting LG boiling, evaporation GLS (exothermic) GL condensation LG freezing SG sublimation GS deposition Temp = average kinetic energy TABLE H: Boiling Point: vapor pressure = atm. pressure Boyle’s Law At constant temperature, volume and pressure are inversely proportional. P1V1 = P2V2 Charles’ Law At constant pressure, volume and temperature are directly related (temp. must be in kelvin) V1 = V2 T1 = T2 Combined Gas Law Used to solve for either pressure, volume, or temperature when no variable is constant. Pressure = atm, kPa, Volume = ml, L, cm3 Temperature = Kelvin Remember that STP = numerical values!!!! P1V1 = P2V2 T1 T2 Avogadro’s Law: Equal volumes of different gases at the same temperature and pressure contain an equal number of molecules. 6.02x1023 molecules = 22.4 L Graham’s Law: Relates the rate of diffusion of gases to their molar masses; the greater the mass, the slower it diffuses, the smaller the mass, the faster it diffuses. Kinetic Molecular Theory: used to describe the behavior of an “ideal gas”. 1. A gas is composed of particles that are in continuous random motion. 2. When gas molecules collide with each other or with the walls of the container, there is a transfer of energy between colliding particles; the total energy remains constant. 3. The volume of gas particles is negligible in comparison with the volume of space they are in. There is a lot of space between the particles. 4. Gas particles are considered as having no force of attraction for each other. “Real gases” deviate from the “ideal gas laws” There are deviations from the four key points made in the KMT. Point 3 Deviation: The volume of gas particles is significant. Gas particles do have some volume. Point 4 Deviation: Gas particles do have a force of attraction. IDEAL GASES: Exist under conditions of low pressure & high temperature. REAL GASES: Exist under conditions of high pressure & low temperature. HYDROGEN and HELIUM are two “real gases” that behave the most like IDEAL gases.