Chapter 15 = Solutions Solutions = homogeneous mixtures containing two or more substances Solute = substance that gets dissolved; smallest part of solution Solvent = substance that does the dissolving; largest part of solution

Solutions are not always made of 2 liquids Carbon + Iron Nitrogen + Oxygen

Soluble = substance that can be dissolved in solvent Sugar and water Insoluble = substance that can not be dissolved in solvent Oil and water

Miscible = two liquids are soluble in each other alcohol and water Immiscible = two liquids are not soluble in each other Oil and water

Solvation- the process of solvent particles breaking apart solute crystals into particles the size of ions http://www.glencoe.com/sites/common_assets/science/cmc/cim/animations/ch14_1.swf

Tyndall Effect Solutions allow light to pass through without being scattered Think about air Non-solutions cause the light to be scattered Think about fog We’ll cover this more in depth in section 15.4

Electrolyte- solutions that can conduct electricity due to ions in the solution

Covalently bonded molecules do not break apart to form ions in solutions but they still do dissolve http://www.glencoe.com/sites/common_assets/science/cmc/cim/animations/ch14_1.swf

Factors that Affect the Rate of Solvation To increase solvation we need to increase the number of times the solute and solvent touch Shake (agitate) the mixture Break to increase surface area Bake—increase temperature

Solubility-maximum amount of solute that will dissolve in a given amount of solvent at a specified temperature and pressure Eventually, solute particles will begin to collide with each other and form crystals.

Unsaturated Saturated Supersaturated Contains less than maximum amount of dissolved solute Saturated Contains maximum amount of dissolved solute Supersaturated Contains more than maximum amount of dissolved solute

If you add extra solute to… Unsaturated Solute will dissolve Saturated Supersaturated Solute will crystallize

Solubility Curves Each substance has its own unique solubility which can be displayed on a graph

Supersaturated solution- solution holding more solute than a saturated solution at the same temperature and pressure Mentos and Diet Coke CO2 is greater than normal levels When Mentos are placed into the CO2 jumps out of solution

Temperature and Solubility SOLID- As temperature increases solubility of a solid solute will increase (few exceptions) GAS- as temperature increases solubility of a gas will decrease

Pressure and solubility Henry’s Law – solubility of any gas increases as the external pressure is increased This is why cokes go flat. When you open the can the external pressure has been reduced and this decreases the solubility of the carbonation (CO2)

If 0. 55 g of a gas dissolves in 1 If 0.55 g of a gas dissolves in 1.0 L of water at 2 atm of pressure, how much will dissolve at 4.5 atm of pressure? 2x = 2.475 X= 1.2375 g/L

A gas has solubility of 0. 66 g/L at 10 atm of pressure A gas has solubility of 0.66 g/L at 10 atm of pressure. What is the pressure on a 1 L sample that contains 1.5 g of gas? 0.66 x = 150 X= 22.73 atm

3. A gas has a solubility of 1. 46 g/L at 8 atm of pressure 3. A gas has a solubility of 1.46 g/L at 8 atm of pressure. What is the pressure of a 1.0L sample that contains 2.7 g/L? answer = 14.8 atm 4. If 0.68 g of a gas at 5 atm of pressure dissolves in 1.0 L of water at 25°C, how much will dissolve in 1.0L of water at 8 atm of pressure and the same temperature? answer = 1.09 g/L