pressure effects - doesn’t affect liquid/solid as much as gas

• increase pressure over solvent >> increase solubility of gas
• gas solubility increases directly proportional to partial pressure above the solution
• Henry’s Law - Sg = kPg
  • Sg = solubility of gas in solution phase
  • Pg = partial pressure of gas over solution
  • k - Henry’s law constant

temperature effects - different for gas/solid

• temperature increase >> solid solubility increase, gas solubility decrease
• thermal pollution - higher temperatures >> lower oxygen solubility in lakes

concentration - dilute (small solute concentration), concentrated (large solute concentration)

• mass percentage = mass of component in solution / total solution mass
  • parts per million = mass percentage x 106
  • parts per billion = mass percentage x 109
• mole fraction - moles of component in solution / total moles of all components
  • molarity (volume) = moles of solute / liters of solution
  • molality (mass) = moles of solute / kilograms of solvent

Find the mass percentage of a KCl solution if it's supposed to be isotonic w/ a 9% NaCl solution 

• assume the mass of solution = 100 g
• 9% NaCl solution >> 9 g of NaCl
• 9g NaCl x 1 mol NaCl / 58.5g NaCl = 0.1538 mol NaCl >> 0.3076 mol solute
• to be isotonic, KCl solution should have same amount of solute
• 0.3076 mol solute >> 0.1538 mol KCl
• 0.1538 mol KCl x 74.5g KCl / 1 mol KCl = 11.5g KCl
• 11.5 / 100 = 11.5% KCl by mass

In a certain ore, there is 1g of Silver for every 500kg of ore. What is the concentration in parts per million? parts per billion?  

• 500kg = 500,000g
• 1 / 500,000 x 106 = 2 parts per million
• 1 / 500,000 x 109 = 2000 parts per billion

Find the molality of chloride ions if 1 g of CaCl2 is dissolved in 750 mL of water  

• for every molecule of CaCl2, 2 Cl- ions are produced when dissolved
• 1g CaCl2 x 1 mol CaCl2 / 111g CaCl2 = 0.009 mol CaCl2 >> 0.018 mol Cl-
• m = mol solute / kg solvent = 0.018 / 0.75 = 0.024

Find the molarity of H2SO4 in a 95% by mass solution if the solution's density is 1.84 g/cm3  

• assume mass of solution = 100 g
• 95% solution >> 95g H2SO4
• 95g H2SO4 x 1 mol H2SO4 / 98g H2SO4 = 0.97 mol H2SO4
• 1.84 g/cm3 = 1.84 g/mL
• 100g solution / 1.84 g/mL = 54.35 mL solution
• M = mol solute / liters solution = 0.97 / 0.05435 = 17.8

colloids (colloidal dispersions) - in between heterogeneous mixtures and solutions

• solutes larger than molecules, not so large that they separate due to gravity
• large enough to scatter light (Tyndall effect)
• hydrophilic (water loving) and hydrophobic (water fearing) colloids in human body
  • hydrophilic groups shield hydrophobic groups from water
  • hydrophobic colloids prepared in water if ions adsorbed (adhered) onto surface
• emulsifying agent - has hydrophilic and hydrophobic end, helps w/ digestion by shielding hydrophobic substances from water
• coagulation - enlarges colloids so they can be removed from solutions
  • caused by heating or adding electrolyte
• semipermeable membranes also remove colloids (ions can pass through, but colloids can’t)