Solutions & Solubility Day 2

Solubility Rules Cu(NO3)2 Use STAAR chart to determine whether or not a compound is soluble (aq) or insoluble (s) Cu(NO3)2 MgCO3 NH4Cl NaOH Mg(OH)2 PbCrO4 Solubility Rules

Solubility and Factors affecting solubility Solubility- the amount of a substance required to form a saturated solution with a specific amount of solvent at a specific temp. ex: the solubility of sugar in water is 204 g/100 ml of water at 20oC.

Factors affecting the RATE OF DISSOLUTION (how fast is dissolves): 1) STIR (agitate)- Brings “fresh” solvent into contact with the solute increasing collisions between particles

2) HEAT - Increases the kinetic energy (particles start moving faster) of the solvent molecules causing more frequent collisions between the solvent and solute

3) Crush/Grind It reduces the particle size and increases the surface area of the solute exposed to the solvent causing more frequent collisions between particles

Factors affecting solubility (how MUCH dissolves) Solubility- the amount of a substance required to form a saturated solution with a specific amount of solvent at a specific temp. ex: the solubility of sugar in water is 204 g/100 ml of water at 20oC.

“Like dissolves like”- 1) Polarity “Like dissolves like”- solubility of a substance is related to the nature of the solvent.

The Solution Process water will dissolve salt “like dissolves like”- like refers to the polarity of the solute and solvent Polar solvents will dissolve POLAR & IONIC solutes water will dissolve salt  water will dissolve sugar Nonpolar solvents will dissolve NONPOLAR solutes  gasoline will dissolve oil

Turpentine (nonpolar) Soluble or Insoluble? Water Turpentine (nonpolar) Br2   NH3

The Solution Process miscible (soluble)- dissolves in all proportions ethanol is miscible in water because they are both polar

The Solution Process Immiscible (not soluble)- vegetable oil is immiscible in water.

The Solution Process oil will not dissolve in water because oil is nonpolar and water is polar

2) TEMPERATURE Increased temp of solids solubility Increased temp of gases solubility GASES SOLIDS

Factors affecting solubility PRESSURE only affects the solubility of gases. pressure, increased solubility (soda) pressure, decreased solubility (fizz) Solubility of liquids and solids is not changed by changes in pressure.

Activity 1: Place a Styrofoam cup in Beaker A. What happens? If beaker A contains water, what can you tell me about the substance Styrofoam? Now place the cup in Beaker B. What happens? Without me telling you what the liquid in Beaker B is, what do you already know about it? Draw and label a picture of this at the bottom of your notes.

FYI… Henry’s Law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas on the surface of the liquid. When a soda fizzes and rapidly releases gas its called effervescence.

Day 2 Activity : Make a small oval shaped pile of shaving cream directly on your table. Spread out with your wood stick. Select 2-3 colors of food coloring and drop 5-6 drops in different locations on the pile. Using a coffee stirrer, MARBLE (don’t whip!) the food coloring through the shaving cream making a swirl pattern.

Write your name decoratively on an index card with Sharpie. Cellulose (in paper) Write your name decoratively on an index card with Sharpie. Dip the card into the shaving cream (name side down). Use a ruler to scrape off the shaving cream.

Now you try!!! Homework…