Question

The cells of a tomato contain mostly an aqueous solution of sugar and other substances. If a typical tomato freezes at -2.5 °C, what is the molality of the sugar in solution? (Hint: sugar is a covalent compound, it does not dissociate in water)

Answer 1

Answer:

1.35 m

Explanation:

We can solve this problem by using the freezing point depression formula:

• ΔT = Kf * m * i

Where:

• ΔT is the temperature difference between the freezing point of the pure solvent (water) and the solution. In this case it is (0 °C - -2.5 °C = 2.5 °C).

• Kf is the cryoscopic constant, for water it is 1.853  °C*kg/mol.

• m is the molality.

• i is the van't Hoff factor, as sugar does not dissociate in water, it has a value of 1.

We input the data:

• 2.5 °C = 1.853 °C*kg/mol * m * 1

And solve for m:

• m = 1.35 m