Chem Worksheet; Colligative Properties. Block:______ Name:________________________________________
Show work, units, and proper sig. figs.
1. What is the molality of a solution of 1.25 moles of sugar dissolved in 0.750 kg of water?
__________ m
2. What is the freezing and boiling point of the solution in Q 1? [For water as the solvent, kb=0.512°C/m; kf= -1.86 °C/m]
fp ________, bp________
3. An aqueous solution was found to have an initial freezing point of -2.15ºC.
What was the molality of the solution?
4. A solution of glucose (M.W. 180.g/mol) in 500.g water had an initial boiling point of 102.25ºC
a. What was the molality of the solution?
________ m
b. How many moles of glucose were added?
__________ moles
c. How many grams of glucose were added?
_________ g
5. 59.2 g of the non-ionizing solute 2-butanol was dissolved in 1.00 kg. of water.
The freezing point was found to be -1.49ºC.
a. What was the molality of the solution?
________ m
b. How many moles of solute we're added?
_______ moles
c. What is the molecular weight of the solute?
_________ g/mol
6. 15.26 g of non-ionizing solute was dissolved in 695 g of water. The initial freezing point of the solution was
measured at -0.623 ºC. What was the molecular weight of the solute?
_________g/mol
7. Pure toluene (C7H8) has a normal boiling point of 110.60ºC. A solution of 7.80 g of anthracene (Cl4H10),
in 100.0g. of toluene has a boiling point of 112.06ºC.
a. What is the molality of the solution?
_______ m
b. What is the molal boiling point elevation constant for toluene?
_______ºC/m
8. 96.5 g of NaCl are added to 650.0g of H2O. What is the freezing pt. of this solution? Boiling pt.?
f pt.________ ºC; b pt.________ºC