Solutions- TEK I9D demonstrate how various factors influence solubility including temperature, pressure, and nature of the solute and solvent A solution is a type of mixture that is homogeneous throughout. Day 3: #1

Types of Solutions  Saturated – a solution which cannot hold any more solute  Unsaturated – a solution in which more solute can be added and which will still dissolve Day 3: #1

Parts of a Solution  Solute-the part that gets dissolved  Solvent-the part that does the dissolving Day 3: #1

How can you increase the dissolving rate of a solid solute in a liquid solvent?  Increase the surface area of the solute (ie, grinding, crushing)  stir or shake the solution  heat the solution Day 3: #1

Solubility - is the maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature.  Increasing Temperature - will increase the solubility of a solid solute in a liquid solvent Example: dissolving sugar in hot tea VS cold tea  Increasing Pressure – will increase the solubility of a gas solute in a liquid solvent Example: carbonated beverages are bottled “under pressure” to increase the amount of carbon dioxide gas in a coke

1. Which of the following salts has the greatest solubility in water at 25°C? 1. Which of the following salts has the greatest solubility in water at 25°C? (F) CaCO 3 (G) FeS (H) HgCl 2 (J) KClO 4 Solubility Rules Solubility Rules 1. All sodium, potassium, and ammonium salts are soluble. 2. All silver, lead, and mercury salts are insoluble. 3. All carbonates, sulfides, and hydroxides are insoluble. 4. All sulfates are soluble except calcium sulfate and barium sulfate.

2. A 0.2 g crystal of gypsum dissolves very slowly in 100 mL of water while the water is stirred. Which of these would cause the gypsum to dissolve faster? F Decreasing the water temperature G Stopping the stirring H Lowering the air pressure J Crushing the crystal Question from TEA released TAKS test

3. All of these can affect the rate at which a solid dissolves in water except — A decreasing air pressure B stirring the water C increasing the temperature of the water D using larger crystals of the solid Question from TEA released TAKS test

4. Over time an open soft drink will lose carbonation (dissolved CO 2 ). Which of these allows the CO 2 to remain in solution the longest? A Reduced air pressure B Exposure to direct sunlight C Increased air currents D Cooler temperatures Question from TEA released TAKS test

5. As a scuba diver goes deeper underwater, the diver must be aware that the increased pressure affects the human body by increasing the – (A) body’s temperature (B) amount of dissolved gases in the body (C) amount of suspended solids in the body (D) concentration of minerals in the body Question from TEA released TAKS test