Worksheet: Cryoscopic and Ebullioscopic Effects

In this worksheet, we will practice using cryoscopic and ebullioscopic constants to calculate how solutes affect solution melting and boiling points.

Q1:

What is the boiling point of a solution of 115.0 g of sucrose, , in 350.0 g of water? The boiling point elevation constant of water is .

Q2:

What is the boiling point elevation of 0.100 kg of water containing 0.0100 mol of , 0.0200 mol of , and 0.0300 mol of ? Assume complete dissociation of the salts.

Q3:

A sample of weighing 9.41 g is dissolved in 32.75 g of ethanol, . The boiling point elevation of the solution is . Is an electrolyte in ethanol?

• ANo, the boiling point elevation is consistent with completely dissociating.
• BYes, the boiling point elevation is consistent with completely dissociating.
• CYes, the boiling point elevation is consistent with partially dissociating.
• DNo, the boiling point elevation is consistent with not dissociating at all.
• EYes, the boiling point elevation is consistent with not dissociating at all.

Q4:

What is the boiling point of a solution of in water if the solution freezes at ? The cryoscopic constant of water is 1.853 K⋅kg/mol and the ebullioscopic constant is 0.512 K⋅kg/mol.

Q5:

What is the boiling point of a solution of 115.0 g of sucrose, , in 350.0 g of water? The boiling point elevation constant of water is 0.512 K⋅kg/mol.

Q6:

Which of the following will have the lowest freezing point?

• AA 0.01 M aqueous solution of
• BA 0.01 M aqueous solution of
• CA 0.01 M aqueous solution of
• DA 0.01 M aqueous solution of
• EA 0.01 M aqueous solution of

Q7:

If a 1.00 M solution of in water shows a freezing-point depression of , what is the freezing-point depression observed for a 1.00 M solution of in water? The ions of both and completely dissociate in aqueous solution.

Q8:

Which of the following will have the highest boiling point?

• AA 0.1 M aqueous solution of
• BA 0.01 M aqueous solution of
• CA 0.1 M aqueous solution of
• DA 0.1 M aqueous solution of sucrose

Q9:

Which of the following has the lowest boiling point?

• AA 12 M aqueous solution of sulfuric acid
• BA 0.01 M aqueous solution of
• CPure liquid water
• DA 0.1 M aqueous solution of glucose

Q10:

What is the freezing temperature of a solution of 115.0 g of sucrose, , in 350.0 g of water? The freezing point depression constant for water is 1.86 kg⋅K/mol.