A solution contains 5.0 g ethylene glycol, C2H4(OH)2, and 95 g water, H2O, by mass. The density of the solution is 1 g/mL. Find the a) freezing point of the solution b) osmotic pressure at 35°C.
a) The freezing point depression:
"\u2206T = k_f \\times c_m"
kf = the molal freezing point depression constant
cm = the molality of the solute
M(C2H4(OH)2) = 62.06 g/mol
n(C2H4(OH)2) "= \\frac{5.0}{62.06} = 0.0805 \\;mol"
c_m = 0.805 M
k_f = 3.11 (from table for ethylene glycol)
∆T = "3.11 \\times 0.805 = 2.50" ºC
The freezing point of the solution = 0 ºC – 2.50 ºC = -2.50 ºC
b) T = 35 + 273 = 308 K
Osmotic pressure:
π = MRT
M = molality of the solution
R = gas constant
T = temperature
"\u03c0= 0.805 \\times 0.082 \\times 308 = 20.33 \\;atm"
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Dear Noel Lecaniel, please post a new question
A system contracts by a volume of 300 cubic cm with a pressure of 1.5atm. Work is equal to _______. a. 450J b. 46J c. -46J d. 0J
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