Answer to Question #231840 in General Chemistry for Zahra

Question

In an investigation to determine the solubility of NaCl in water, methanol and hexane, a student adde 40.0 g of NaCl

to 100.0 ml of each liquid maintained at a temperature of

25’ c.after 2 minutes of stirring each mixture, the mass of undissolved salt was determined through filtering the mixture and weighing the residue.the results of the investigation are shown below.

liquid Mass of NaCl (s)

Recovered by filtration

hexane 39.9

methanol 38.6

water 3.85

a .

place the liquids tested in order of their increasing solubility of NaCl

b.

explain the trend in solubility of NaCl in the three liquids using your knowledge of the process by which ionic solids dissolve and the intermolecular forces involved.

Answer 1

a) water, methanol, hexane

b) The increase in kinetic energy that comes with higher temperatures allows the solvent molecules to more effectively break apart the solute molecules that are held together by intermolecular attractions.

The increased vibration (kinetic energy) of the solute molecules causes them to dissolve more readily because they are less able to hold together.