QQ: Answer on a sticky note to hand in. Think about this that went well in this class over the past week. List 3 things here. List three things that need improvement. List 3 ways to make this 90 minute period better. What 3 things are YOU going to do to make this class better?

Projects are due on Tuesday….February 21! Funny? Not so funny? 25% of Overall grade Projects are due on Tuesday….February 21!

Today’s Objective: Using a solubility graph, I can determine how much solute can be added to a solution.

Completing the lab…..

Endo or Exo?????

Solutions: Heterogenous, Homogeneous, Colloid, Suspension

Solute: Substance you pour in Solvent: The receiving substance Parts of Solutions: Solute: Substance you pour in

physical or chemical changes. Solutions can be physical or chemical changes. Chemical changes can NOT be separated back to original parts. Physical changes can be separated back to original parts.

Solubility: The amount of a substance that can be dissolved

Can not hold more without precipitant forming Saturated Can not hold more without precipitant forming

Unsaturated Can hold more solute – no precipitant

Super-Saturated Made to hold more than normal, usually by heating

Factors That Affect Solubility 1. Nature of the reactants 2. Polarity

3. Temperature: Heating up allows more solute to be dissolved.

4. Surface area Increase the surface area will increase the rate it dissolves.

5. Stirring will increase the surface area exposed and increase solubility.

at a certain temperature Solubility Curve G in H20 Temp C Graph showing how much can be dissolved at a certain temperature

Super-saturated G in H20 Saturated Temp C Unsaturated

Solubility Curves

Webwhiteboard.com

In the Physical Science Book: Complete problems 1-5 on page 71. Answer your problems completely and with detail.

Describe a solution at 30C with 50 g Saturated

Which substance is most soluble in H20? Yellow, NaNO2 under 70C Blue, KNO3 over 70C Which substance is most soluble in H20?

Supersaturated Describe the saturation of a solution containing 100 g of potassium bromide solution at 60 C

Sodium Nitrate The most soluble at 0 C

Solubility increases most between 40 & 60 C Sodium Acetate Solubility increases most between 40 & 60 C

Changes the least as temperature changes Table Salt Changes the least as temperature changes

How would cooling a solution affect its solubility? It would hold less solute.

It would increase. How would decreasing the size of a solute’s particle affect its solubility? It would increase.

A super saturated solution is cooled to room temperature A super saturated solution is cooled to room temperature. What would it create? Crystals

When will more salt dissolve than sugar? Never, Sugar’s curve is always above salt Sugar Salt When will more salt dissolve than sugar?

Unit Exam Friday