Solutions

Homogeneous mixture made of two or more substances Solid-solid Concentrated Dilute Solute Solvent a lot of solute little solute gets dissolved does the dissolving Solubility : the ability to be dissolved temperature dependent Solutions Homogeneous mixture made of two or more substances Solid-solid Solid -liquid Liquid-liquid Liquid-gas Gas-gas (aq)

= -does not hold the maximum -more can be dissolved -Under the line miscible Two substances that can be mixed together g/100g H2O immiscible Two substances that can not be mixed together temperature unsaturated saturated supersaturated tincture -does not hold the maximum -more can be dissolved -Under the line -does hold the maximum -no more can be dissolved -on the line At equilibrium Settles on the bottom -holds more than the maximum -no more can be dissolved -fallout, b/c unstable -above the line Solvent is alcohol - MUST BE HEATED AND THEN COOOLED =

Table G- Solubility Curve

Surface area temperature Agitation Solubility Polar solvents dissolve polar and ionic substances the ability to be dissolved temperature dependent Like dissolves like Non-Polar solvents dissolve non-polar substances Factors that Influence Solubility Solids Gas Surface area Increase Temperature Increase the solubility of a solid Increase Temperature decrease the solubility of a gas Temperature Factors that increase the dissolving rate temperature Increase pressure Increase the solubility of a gas Increase pressure No effect on the solubility of a solid Pressure Agitation

Measuring Concentration What is the molarity of a solution that has 25 g of NaCl dissolved in 500 ml of water? The concentration of solute in solution expressed as number of moles of solute dissolved in 1 liter of solution. Moles per liter Symbol M moles of solute liters of solution M= Molarity Percent by Mass The concentration of a solution is expressed as a percent (mass/mass) Percent by Mass = Mass of solute Mass of solution What is the % mass of 58g of glucose in a 2000g Solution? x 100 Parts Per Million A unit of concentration that expresses the mass of a solute dissolved in 1 million parts of a very dilute solution. Grams of solute Ppm= x 1,000,000 Grams of solution How many parts per million are in a solution of 10g of NaCl in 100g of water? 10 X 1,000,000 110 25/58= 0.43 mol 500/1000= 0.5L 58 X 100 2000 0.43 = 0.86M 0.5 90,909ppm 2.9%

Effect of Ionic Substances on the Boiling and freezing point : The more ions you have the higher the boiling point and the lower the freezing point!!!

Colligative Properties-- factors that determine boiling and freezing point of a liquid by the changing the concentration of solute (number of particles) Boiling Point Elevation When a nonvolatile solute is added to a solvent , the boiling point will increase When a nonvolatile solute is added to a solvent , the freezing point will decrease Freezing Point Depression Effect of Electrolytes A solution that can conduct electricity due to the presence of ions Ionic-- metal/nonmetal --- splits NaCl --- Na+ + Cl- --- 2 particles Covalent --nonmetals -- do not split C6H12O6---C6H12O6---- 1 particle Need to look at how many particles are produced when solute dissolved Other examples: Ba(NO3)2------Ba2+ + 2 NO3- -----3 particles- CH3OH----- does not split ---CH3OH one particle The more particles you have, the greater the change

How to make a solution: 1. AAA- Always Add Acid to dilute 2. a. Weigh out solid b. Add solid to container c. Add some solvent to the container d. Mix until it all dissolves e. Add solvent until you get the required volume

Use the following formula: MAVA= MBVB TABLE T Molarity by Dilution- Concentrated solutions can be mixed with solvent to make weaker or dilute solutions. In dilutions the amount of solvent is increased, but the amount of solute is kept constant. The result is a decreased concentration, but a greater volume. number moles original = number of moles final Use the following formula: MAVA= MBVB TABLE T Ex. You have 50.0mL of a 1.5M solution of NaCl, but you need 0.80M solution for your lab. How many mL can you make of the 0.80M if you use all of the 1.5M stock? MAVA=MBVB 1.5(50)=0.8x 75 = 0.8x x= 93.75mL Ex. A stock bottle of HCl has a concentration of 12.0M. The lab requires 500mL of 3.00M HCl. How many milliliters of the stock solution will you need to make your working solution for the lab? MAVA= MBVB 3.00(500)=12x X= 125mL