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

Solutions A 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.

Solutions Recall, 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: Add more solute than solubility allows Heat the solution up Slowly cool it down This is a temporary and unstable state for a solution!

Factors that affect solubility: Temperature: most solid substances have higher solubility as temperature increases All gas solutes have lower solubility as temperature increases Pressure: only affects gas solutes All gas solutes have higher solubility as pressure increases

Solubility Curves For 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: Increasing temperature- There is more kinetic energy available to meet the activation energy (energy available for dissolving) Stirring- Increases the interaction between solute and solvent 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 = miscible Polar + Polar = miscible Non-polar + Polar = immiscible As a general rule: “Like dissolves like”

Concentration Indicates the amount of solute dissolved in a given quantity of solvent. Dilute: a small amount of solute Concentrated: a large amount of solute

Questions? Begin WS1