Solutions

Vocabulary Solution: homogeneous mixture (can be S, L, or G) Solute: substance that dissolves Solvent: substance in which the solute dissolves

Vocabulary Cont’d Insoluble: substance that cannot be dissolved Soluble: substance that can be dissolved Miscible: 2 liquids mix completely Immiscible: 2 liquids that do not mix completely

Soluble vs. Insoluble “Like dissolves Like” Rule: Only substances that are similar/alike will dissolve into one another Polar and Polar (dissolve) Nonpolar and Nonpolar (dissolve) Polar and Nonpolar (do NOT dissolve) Water is Polar! (IMPORTANT)

Water Must be able to draw water!

Saturation Unsaturated: when a solution can hold more solute and it does dissolve Saturated: when a solution cannot dissolve any more solute Supersaturated: contains more solute than a saturated solution at the same temperature extremely unstable and if a small amount of solute (seed crystal) is added the excess solute quickly falls out of solution (Example: hand warmers, rock candy, and cloud seeding)

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

Heat of Solution Endothermic: energy is put into the compound (feels cold) Exothermic: energy is released from the compound (feels hot) The overall change is the heat of solution

Dissolving & Solubility Factors that can effect the RATE (how fast/slow) dissolving: Temperature Stirring/Agitation Surface Area

Temperature and Solubility Solids Increase Temp. will Increase Dissolving (Solubility) Decrease Temp. will Decrease Dissolving (Solubility) Gases (Different from Solids) Increase Temp. will Decrease Dissolving (Solubility) Decrease Temp. will Increase Dissolving (Solubility) Increase Pressure will Increase dissolving. Decrease Pressure will Decreases dissolving.

Solids dissolved in liquids Gases dissolved in liquids To Sol. To Sol. As To , solubility As To , solubility

Water and Oxygen Dissolved Oxygen – The amount of oxygen that is dissolved in water If dissolved oxygen is too low, animal and aquatic life is unable to survive and the water becomes toxic Happens commonly in lakes and ponds during the summer months

Temperature and Solubility Solubility of a gas increases as the external pressure increases When pressure on the outside decreases some of the gas escapes. Henry’s Law – At a given temperature the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) above liquid S1P2 = S2P1

Practice If 0.24 g of a gas dissolves in 1.0L of water at 1.5 atm of pressure, how much of the gas will dissolve if the pressure is raised to 6.0 atm? Assume the temperature is held constant. The solubility of a gas changes from 0.95 g/L to 0.72 g/L. If the initial pressure was 2.8 atm, what is the final pressure?

Concentration How much solute is dissolved in a specific amount of solvent or solution. Can be expressed as Percent by mass Percent by volume Molarity

Percent by Mass (Mass of solute/Mass of solution) x 100 Used when a solid is dissolved in a liquid Mass of solution is equal to the mass of the solute + the mass of the solvent

Percent by mass problems In order to maintain a sodium chloride concentration similar to ocean water, an aquarium must contain 3.6 g of NaCl per 100 grams of water. What is the percent mass of the solution? What is the percent by mass of NaHCO3 in a solution containing 20 grams of NaHCO3dissolved in 600 ml of water?

You have 1500 grams of bleach solution You have 1500 grams of bleach solution. The percent by mass of the solute is 3.62%. How many grams of NaOCl are in solution? How many grams of solvent are in the solution?

Percent by Volume Usually describes solutions where both solute and solvent are liquids Volume of solute/Volume of solution x 100

What is the percent by volume of ethanol in a solution that contains 35 ml of ethanol distilled in 115 ml of water? If you have 100 ml of a 30% aqueous solution of ethanol, what volumes of ethanol and water are in the solution? What is the percent by volume of isopropyl alcohol in a solution that contains 24 ml of isopropyl alcohol in 1.1 L of water?

Molarity Its unit is a M = mol/L Moles of solute/Liters of solution A 100.5 ml solution contains 5.10 grams of Glucose (C6H12O6). What is the molarity of this solution? The molar mass of glucose is 180.18 g/mol

Calculate the molarity of 1. 60 liters of a solution containing 1 Calculate the molarity of 1.60 liters of a solution containing 1.55 grams of dissolved KBr. What is the moles of solute in a solution with a molarity 9.5 M and 25 mL of solution? What is the molarity of an aqueous solution containing 40 grams of glucose in a 1.5 L of solution?

A 100. 5 ml IV solution contains 5. 10 grams of Glucose (C6H12O6) A 100.5 ml IV solution contains 5.10 grams of Glucose (C6H12O6). What is the molarity of this solution? The molar mass of glucose is 180.18 g/mol

Making a molar solution Using the molarity of the solution figure out how many moles of the solute will be needed. Using the moles of solute, convert it to grams of solute How many grams of CaCl2 would be dissolved in 1.0 liters of a .10M solution? A liter of 2M NaOH solution has how many grams of NaOH?

How many grams of CaCl2 should be dissolved to make 500 ml of a How many grams of CaCl2 should be dissolved to make 500 ml of a .20M solution? How many grams of NaOH are in 250 ml of a 3.0M solution?

Diluting a stock solution Stock solution is a concentrated solution M1V1 = M2V2 What volume in ml of 2.00M CaCl2 stock solution would you use to make 0.50 L of 0.300M calcium chloride solution? What molarity of a 300 mL KI stock solution would you use to make 0.300 L of a 1.25 M KI solution?

If you dilute 20. 0 ml of a 3. 5M solution to make 100 If you dilute 20.0 ml of a 3.5M solution to make 100.0 ml of solution, what would the molarity of the diluted solution be? How many ml of a 5.0M H2SO4 stock solution would you need to prepare 100 ml of 0.25 M H2SO4?

Viscosity Fluids resistance to flow Fluid pours fast ________ viscosity Fluid pours slow ________ viscosity

Dissolving Ionization: The breaking up of a compound into separate ions Electrolyte: A substance whose aqueous solutions conduct electricity Nonelectrolyte: A substance whose aqueous solutions do not conduct electricity

Name Formula Ionic / Covalent Soluble / Insoluble Electrolyte or Precipitate