Osmotic pressure Water flows from areas of high water concentration to regions of low water concentration o Low solute concentration high solute concentration Sugar solution in bag has higher osmotic pressure than pure water around it Seawater filtration used for small communities because it s more practical quite expensive o Apply pressure on seawater to force water through semipermeable membrane to separate freshwater from the concentrate flow Solute particles same size as solvent particles doesn t work as well Bowl of chicken noodle soup with lots of salt very high solute concentration compared to inside germ cells water flows out of germ cells faster than cell wall can accommodate so they implode and you feel better If two solutions have equal concentrations isotonic Bag of 5 sugar 95 water in pure water o Pure water hypotonic o Sugar water hypertonic Clicker What happens in each of the following cases in a U tube Solution A Solution B 1 m glucose 2 m glucose water would rise on side B 0 5 m glucose 0 5 m galactose water would not rise on either side 1 w w glucose 3 w w glucose water would rise on side B 3 Ethylene glycol 3 galactose water would rise on side A Assume we have 3 grams in 100 grams of solution ethylene glycol will have more moles particles due to its smaller molar mass Clicker rank the following solutions from lowest boiling point to highest boiling point A 0 35 m Ethylene glycol C2H6O2 B 0 20 m KBr C 0 50 m glucose C6H12O6 D 0 21m Na2SO4 ABCD KBr s K aq Br aq dissociates into two ions so concentration is 0 40 m in particles Na2SO4 actually has 0 63 m in particles Clicker A 0 0200 m aqueous solution of an ionic compound Co NH 3 4Cl3 freezes at 0 0640 C What is the van t Hoff factor for this compound Kfp for water is 1 86 T kfpm 0 0640 C 1 86 x 0 0200 m 1 72 i of moles particles 1 mole solute particles i m calculated m stated Tfp actual Tfp calculated T kfpm Clicker A 0 100 M acetic acid solution has an osmotic pressure of 2 47 atm at 25 C What is the percent ionization of acetic acid in the solution CH3COOH H2O CH3COO H3O ionization amount dissociated mol L initial concentration mol L x 100 Initial concentration 0 100 M CH3COOH CH3COOInitial 0 100 M 0M Change X X Equillibrium 0 100 M X X Mpart 0 100 X X X 0 100 X Osmotic pressure MRT M osmotic pressure RT 2 47 0 0821 x 298 0 101 M Mpart 0 101 M 0 100 X X 0 001 0 001 0 100 0 01 x 100 1 H3O 0M X X ICE chart easy way to organize the data to make it easy to do calculations Going to use them a lot in chapter 16 chemical equilibrium Initial situation What change occurs What would equilibrium situation be Ex of ICE chart for A B C D A B C D Initial 1M 2M 0M 0M Change X X X X Equillibrium 1 X 2 X X X Clicker Smell of ripe raspberries is due to 4 p hydroxyphenyl 2 butanone which has the empirical formula C5H6O To find its molecular formula you dissolve 0 135 g in 25 0 g of chloroform CHCl 3 The bp of the solution is 61 82 C What is the molecular formula of the solute Given CHCl3 BP 61 70 C Kbp 3 63 C m Need the molar mass to convert empirical formula to molecular formula MW g solute mol solute Molar mass 164 2 g mol C10H12O2