unit 11: acids, bases, and solutions introduction to solutions
TRANSCRIPT
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