Solution A solute is dissolved in a solvent. By this definition…  What is a solute?  What is a solvent? Are solutions solid, liquid or gas?

Liquid Solutions What are some common solutions? How do we know which dissolved what?

Nonliquid solutions A gaseous solution? A solid solution?  Alloys

Ponder this… How do vending machines verify the size, weight, and electrical conductivity of coins?

Dissolve it! How? (An example using sugar)  Step 1 Oppositely charged parts of the sugar and water molecules attract each other.  Step 2 Water molecules pull the sugar molecule away from the crystal.  Step 3 Water and sugar molecules spread out until a homologous mixture forms.

Quicker than… MiniLab  Materials: 4 sugar cubes, distilled water, 2 beakers, 2 stirring rods, mortar and pestle, stopwatch, graduated cylinder  Methods: Grind up 1 sugar cube Place the ground sugar cube in a beaker. Place the whole sugar cube in the other beaker. Add an equal amount of water to each beaker. DO NOT disturb the beakers. Observe the length of time it takes for the sugar to dissolve completely. Repeat the lab, but stir the sugar water.

MiniLab Analysis 1. Compare the times required to dissolve each sugar mixture, both not stirred and stirred. 2. What do you conclude about the dissolving rate and surface area? 3. What do you conclude about the dissolving rate and stirring?

Stirring Why stir?

Surface Area What is it? Examples  Find the surface area of a 1 cm cube.  Find the surface area of a 1 cm cube that has been cut in half. Your turn…  A 5 cm cube of salt is attached along a face to another 5 cm cube of salt. How much surface area is lost by combining the cubes to form a rectangular solid?

Temperature Why would temperature effect the rate of a reaction?

Controlling a Reaction With your new knowledge what would you do to increase the rate of a reaction? What would you do to decrease the rate of a reaction?

Controlling Gas Solutions Gases dissolve faster... Gases dissolve faster...  no shaking or stirring  high pressure  low temperature

Concentration, not focusing What is concentration and why do we care? % by volume…  EX: 10% juice = 10mL juice + 90mL water % by mass…  EX: 20% NaCl = 20g NaCl + 80g water

Molarity Example: If 5.00 g of NaCl dissolved in 5000 mL of solution, what is the molarity of the solution? First step: Convert the amount of NaCl in grams into moles: Second step: Simply use the definition of molarity: moles/liters to get the answer

How much can we dissolve? Solubility?!?  Two players: Amount Temperature

Comparison of solubility State of SubstanceSubstanceSolubility (g/100 g of H 2 O) Solid Salt35.9 Baking soda9.6 Washing soda21.4 Lye109.0 Sugar203.9 Gaseous Hydrogen Oxygen0.005 Carbon dioxide0.16

Solutions SATURATED SOLUTION no more solute dissolves UNSATURATED SOLUTION more solute dissolves SUPERSATURATED SOLUTION becomes unstable, crystals form concentration

Ponder… What is the difference between solubility and concentration?