A solution is prepared by mixing 1.0 grams of benzene (C6H6) in
100 g of water to create a solution total volume of 100 ml. Calculate the molarity, mass
percent, mole fraction, and molality of benzene in the solution.
Which ion would you expect to be more heavily hydrated?
Assuming the CO2 partial pressure in air above a lake at sea level is 4.0 x
10-4 atm, what is the equilibrium concentration of CO2 in the lake
at 25oC? (Henry’s law constant is 32 L . atm / mole)
A cocktail was prepared by mixing 20.0g ethanol to 150 g water at 25oC. Pure
water has a vapor pressure of 23.76 torr. What would be the new vapor pressure?
10 grams of salt (NaCl) is added to 100 mL of water. What are the new freezing and
boiling points? (Kb = .51 oC kg/mol, Kf = .1.86 oC
Calculate the pressure needed to prevent osmosis when 10.0 g CaCl2 is added
to 100 mL of water?
(.0128 moles benzene) / (.1 kg water) = 1.28 mole/Kg
Ca2+ should be more heavily hydrated because there is a greater attractive
force due to the extra charge making D H3 more
negative. D H1 and D H2
are going to be similar because these are similarly sized ions.
Na+ should be more heavily hydrated because it is the smaller ion, which will
decrease D H1 and D H2.
Cu2+ should be more heavily hydrated because of the same reasons as in part
PCO2 = kCO2CCO2
CCO2 = PCO2 / kCO2
CCO2 = 4.0 E-4 atm / 32 L atm/mol
CCO2 = 1.2 E-5 mol/L
P = c solvent Po
20 g ethanol / 46 g/mol = .44 mol ethanol
150 g water / 16 g.mol = 9.4 mol water
c solvent = 9.4 mol water / (9.4 mol water + .44