Entire Chem 1B Lecture/Textbook Notes.doc

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Athan J Shaka

Chap 5 • gases • o assume volume and shape of container o most compressible states of matter o low density compared to liquids/solids o have no order (mix with other gases evenly) • pressure • o force applied per unit area o  pressure = force/area o measurements o  pascal (Pa)   1 Pa = 1 N/m^2  psi   pound per square inch  atm (aka bar)   atmospheric pressure  100,000 Pa = 14.7 psi = 1 atm = 760 mmHg (torr) • Boyle's law • o pressure is inversely proportional to volume (if everything else is constant) o pV = k • Charles's law • o volume is directly proportional to the temperature (if everything else is constant) o V = kT • Avogadro's law • o volume of gas is directly proportional to the # of moles (if everything else is constant) • ideal gas law • o o  R = gas constant (.0821 (L*atm)/(K*mol)  n = # of moles • kelvin - 273.15 C • J = N*m = Kg m^2/s^2 • Van der Waals equation • o takes into account attraction and repulsion forces o o a is the attraction force (larger # w/more electrons) o  L^2 * atm/mol^2 o b is the repulsion force (larger # w/larger gas particles) o  L/mol • Dalton's law of partial pressures • o total pressure of a mixture of gases = sum of the pressures if each gas stood alone (pressure of A + pressure of B...) o o  pressure of something = .00% of that thing * pressure of the entire thing o SLIDE ex ? • Kinetic theory of gases • o molecules are separated in space by many molecular diameters o  molecules have mass but negligible volume o gas molecules collide and move randomly o  total energy of all the molecules in a system remains the same o there are no attractive or repulsive forces o  wrong because of VdW but is mostly ok for traditional gases. leads to Dalton's law o the average kinetic energy of gas molecules is proportional to temperature o  as long as there are no other forces • Maxwell • o at a given instant, how many molecules are moving at a particular speed o o  the hotter, the faster. The lighter the faster. o the average speed of a molecule at any T (root mean square speed) o   M = kg/mol  R = 8.314472 J/(mol*K)  end units will be m/s  at any temp, all molecules have the same average kinetic energy. but, lighter molecules move faster • diffusion • o spreading of gas molecules o lighter molecules spread quicker then heavy (they move faster) • effusion • o gas escapes through a small opening to a lower pressurized area o Graham's law of diffusion o    rate or time it takes to effuse  m = molar mass o Sapling Chap 6 • solute is dissolved in the solvent to create a solution • types of solutions • o saturate - contains max amount of solute o unsaturated - can contain more solute o supersaturated - contains too much solute, will exist in 2 phases • reactions in a solution • o solvent-solvent interaction o solute-solute interaction o  if these two interactions are stronger then the last, the solution process is endothermic (deltaHsoltuion > 0)  still has possibility to happen because entropy o solvent-solute interaction o  if this is stronger then the other 2, solution process is exothermic and favorable (deltaHsolution < 0) • miscible • o can dissolve in any proportion (for ex. something with hydro bonds can dissolve in water very easily, no matter the fraction) • concentration units • o o o o • BP of a solution • o o K is the ebullioscopic constant o  water - .512 C/m o i = moles of particles solute makes o  organic molecules are non-electrolytes and therefore have an i = 1  electrolytes have an i of however many particles they break into   NaCl = 2  C6H5COOH = 2 o m = molality • FP of a solution • o o k is the cryoscopic constant o  water - -1.858 K·kg/mol or 1.86 C/m • VP of a solution • o o vapor pressure of pure water is higher than vapor pressure of solution • Osmotic Pressure • o pressure required to stop osmosis o o o  osmotic pressure = (i)(molarity of solution)(.0821Latm/Kmol) (absolute temperature)  osmotic pressure = atm • Colloids • o do not dissolve o ex o  fog - liquid in gas  smoke - solid in gas  mayonnaise - liquid in liquid o surfactant o  hydrophilic head, hydrophobic tail   creates micelles to remove grease Chap
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