Unit 11: Acids, Bases, and SolutionsIntroduction to Solutions

After today you will be able to…

•Explain the differences between the three different types of solutions

•Describe how to make a supersaturated solution

•Describe how to increase the rate of dissolving

A solution is a homogeneous mixture. The components are not chemically combined and retain their original properties.Example: Sugar water – still tastes sweet

SolutionsA solution is made up of a solute and solvent.•Solute: a dissolved substance•Solvent: the most abundant component of a solution, what does the dissolving

Water is called the “universal solvent” because it has the

ability to dissolve so many substances.

SolutionsRecall, aqueous is a solution where water is the solvent.Example:

NaCl(aq) Na+ + Cl-

Solubility The maximum amount of solute dissolved in a particular solvent at a specific temperature.•Saturated: No more solute can dissolve•Unsaturated: More solute can dissolve•Supersaturated: More solute is dissolved than theoretically possible

To make a supersaturated solution:

1. Add more solute than solubility allows

2. Heat the solution up3. Slowly cool it down

This is a temporary and unstable state for a solution!

Factors that affect solubility:

1. Temperature: most solid substances have higher solubility as temperature increases• All gas solutes have lower solubility

as temperature increases2. Pressure: only affects gas solutes• All gas solutes have higher

solubility as pressure increases

Solubility CurvesFor Solid Solutes:

For Gas Solutes:

Rate of dissolving: How fast a solute dissolves in a solvent – not to be confused with how much.

Rate can be increased by:

1. Increasing temperature- There is more kinetic energy available to meet the activation energy (energy available for dissolving)

2. Stirring- Increases the interaction between solute and solvent

3. Powdering- Increase surface area of the solute which increases the interaction between solute and solvent

Liquid-Liquid Solutions• Miscible: two liquids which uniformly

mix together (ex: milk and water)• Immiscible: two liquids which will not

mix, forms two layers (ex: oil and water)

Non-polar + non-polar = misciblePolar + Polar = miscible

Non-polar + Polar = immiscible

As a general rule: “Like dissolves like”

ConcentrationIndicates the amount

of solute dissolved in a given quantity of solvent.•Dilute: a small amount of solute•Concentrated: a large amount of solute