chapter 4: solutions

Question 1

Formation of Solutions involve:

Answer 1

• Bond breaking
• > Bond between solute particles broken as particles move away to mix with solvent.
• > Bond b/w solvent particles disrupted as solute particles move inbetween them.
• Bond Forming
• > New bonds formed between solute particles and solvent particles.
• The relative strengths of the bonds that need to be broken and the new ones formed is a major factor in determining whether a solution forms.

Question 2

Mixing Polar solutes and Polar solvents

Answer 2

• Like dissolves like
• The bonds of the solute need to be equal / stronger than bonds of solvent in order to break them,
• • A solute with hydrogen bonds between the molecules should dissolve in water because the new bonds formed between the solute and water are also hydrogen bonds.

• A solute with only dispersion forces between its molecules (i.e. a non-polar solute) will not dissolve in water because hydrogen bonds need to be broken between the solvent (water) molecules, but only dispersion forces can form between the solute and solvent molecules.

Question 3

Predictions concerning solubility can be made using:

Answer 3

• Polar solutes will dissolve in polar solvents
• Non-polar solutes will dissolve in non-polar solvents
• The solubility of a polar solute decreases as the polarity of the solvent decreases
• The solubility of a non-polar solute increases as the polarity of the solvent decreases

Question 4

Dissolving Ionic Compounds in Water

Answer 4

• Ion-dipole forces exist b/w ions and polar molecules
• > stronger than hydrogen bonds
• Positive ions attract the partially -ive charged end of H2O
• negative ions attract the partially +ive charaged end of H2O