Solutions & Colligative Prop.

A 250 mL solution containing 21.4 g of polymer in toluene had an osmotic pressure of 0.055 atm at 27 ^oC. What is the formula weight of the polymer?

• 15,000 g/mol
• 26,000 g/mol
• 32,000 g/mol
• 38,000 g/mol

The vapor pressure of a solution containing a nonvolatile solute is directly proportional to the

• molality of the solvent
• osmotic pressure of the solute
• molarity of the solvent
• mole fraction of the solvent

The vap. pres. of pure water at 85 ^oC is 434 mmHg. What is the vap. pres. of a solution of 100 g of water & 150 g of diglyme, C_6H_14O_3, a nonvolatile substance? 

• 361 mmHg
• 390 mmHg
• 425 mmHg
• 388 mmHg

What observation(s) reflect(s) colligative properties?
I. A 0.5 m NaBr soln has a higher vapor pressure than 0.5 m BaCl_2 soln.
II. A 0.5 m NaOH soln freezes at a lower T. than pure water.
III. Pure water freezes at a higher T than pure methanol.

• only I
• only II
• only III
• 1 & II

Calculate the mole fraction of ethanol, C_2H_5OH, in a solution that contains 46 g of ethanol & 64 g of methanol CH_3OH.

• 1/3
• 0.42
• 1/2
• 2/3

What is the molality of an aqueous solution labeled "8.6% glucose (C_6H_12O_6) by mass?"

• 0.26 m
• 0.34 m
• 0.44 m
• 0.52 m

Consider the following liquids.  Which pairs are miscible?
1. benzene & hexane
2. water & methanol (CH_3OH)
3. water & hexane

• 1, 2 only
• 2 only
• 1 only
• 1, 2, 3

Tags

NGSS.HS-PS1-3

What is the freezing point of an antifreeze solution created by adding 651 g of ethylene glycol (CH_2(OH)CH_2(OH)) to 2505 g of water? K_f = 1.86 ^oC/m

• -4.19 ^oC
• 2.2 ^oC
• 0 ^oC^
• -7.79 ^oC

The average osmotic pressure of seawater is about 30.0 atm at 25 ^oC. Calculate the molar concentration of a sucrose solution that is isotonic with seawater.

• 1.23 M
• 0.813 M
• 0.0121 M
• none of these

58 grams of NaCl is added to 2 kg of water. What is the molality of the solution?

• 29 m
• 1 m
• 0.50 m
• none of these