Weak solute-solute interactions, weak solvent-solvent interactions, and strong 

solute-solvent interactions.

Consider the following rate law,      rate = k [A] ³

What happens to the rate of reaction 

if the concentration of A is doubled (assume the temperature remains constant)? 

• Reactants are consumed 

• Products are formed 

• There is a transfer of energy.

The solubility of a solute is the maximum amount solute that can be dissolved in a specified quantity  of solvent  at a constant temperature and pressure (and result in 

stable solution).

Colligative property

A physical property of a solution which depends on the number of 

solute particles in a given amount of solvent, but not on the identity of the solute particle(s)

Miscible

During lecture the dissolution process was described as consisting of three steps.  

Describe each of the three steps and include if it the step is endothermic or exothermic. 

1) Expand the solute:  The attractive forces between solute particles must be overcome 

(break the intermolecular attractive forces which exist between solute particles).  

Endothermic, ΔHsolute. 

2) Expand the solvent:  The attractive forces between solvent particles must be 

overcome (break the intermolecular attractive forces which exist between solvent 

particles).  Endothermic, ΔHsolvent

. 

3) Intermolecular interactions develop between individual solute and solvent particles 

(solute particle – solvent particle attractions form).  Exothermic, ΔHmix.

Describe what is meant by the phrase “like dissolves like.”  Use this principle to determine if the solute will 1) dissolve in the solvent (label with the letter “D) or 2) will not 

dissolve in the solvent (label with “ND”).

HCN  in CCl4 ND,  HCN is polar (dipole-dipole interaction) 

and CCl4 is nonpolar (London interaction) 

CaCl2 in H2O 

D, CaCl2 is polar (i.e it is an ionic compound) 

and H2O is polar (a Hydrogen bond is a 

strong dipole-dipole interaction) 

Like dissolves like:  A solute is more likely to dissolve in a solvent if both the solute and 

solvent have similar intermolecular forces.

The solubility of a solid or liquid generally increases as the temperature increases 

(exceptions do exist).

For all practical purposes, the solubility of a solid or liquid does not depend on 

pressure. 

594.0 g of NaCl is dissolved in 3.780 kg of water.   Determine the freezing point of 

the resulting solution.  Don’t forget about n (i.e. the van’t Hoff factor), kf

 H2O = 1.86°C/m.