Chapter 13 Notes Solutions

13.1: The Nature of Solutions 1. Solution: A homogeneous mixture of 2 or more substances in a single physical state (visibly the same throughout.) A. Properties of Solutions: 1. small particles 2. particles are evenly distributed 3. particles won’t separate when allowed to stand 4. every substance has it’s own solubility

B. Vocabulary: Solute: substance that is dissolved (usually  50% of solution) Solvent: substance that does the dissolving (usually  50% of the solution) Soluble: means something can be dissolved in a solvent. Ex) salt in H 2 O Insoluble: means something cannot be dissolved in a solvent. Ex) iodine in water solvent solute

C.Types of Solutions: 1. Solid Solutions (solid solute) Alloys: solid solution that contains two or more metals. Ex) steel – 99% iron & 1% carbon, gold jewelry, brass Advantages of alloys over pure metals: stronger, corrosion resistant, cheaper, attractive color

2. Gaseous Solutions: (gaseous solute) The properties of gaseous solutions depend on the properties of its compounds. Ex) air 3. Liquid Solutions: (liquid solute) Miscible liquids: Two liquids that are able to mix together in any proportion. Ex) alcohol & water

Immiscible liquids: Two liquids that are unable to mix together in any proportion. Ex) oil & water (lava lamps)

Aqueous Solutions: Solutions with H 2 O as the solvent. Because water can dissolve so many things, it is called the universal solvent. Tincture: Solutions with alcohol as the solvent. Ex) iodine & alcohol

Electrolyte: ionic compounds dissolve in water to form ions that can conduct an electric current. Ex) salt & water Electrolyte Nonelectrolyte

Nonelectrolyte: molecular (covalent) compounds dissolve in water to form molecules that cannot conduct an electric current. Ex) sugar & water

D. Separating Solutions: Done through a change of state - evaporation or condensation. (distillation)

Type of SolutionSpecific SoluteSpecific Solvent Gas in Gas Air O2O2 N2N2 Gas in Liquid Soda CO 2 H2OH2O Gas in Solid catalytic converter hydrocarbons Pt Liquid in Gas fog H2OH2Oair Liquid in Liquid Lemonade lemon juicewater Liquid in Solid teeth fillings mercurysilver Solid in Gas smoke carbonair Solid in Liquid Kool-Aid sugarwater Solid in Solid steel carboniron IN

13.2: Concentrations of Solutions A. Terms Used for Concentration: The amount of solute in a given amount of solvent or solution. 1. Concentrated: When a solution has a large amount of solute compared to solvent. 2. Dilute: When a solution has a small amount of solute compared to solvent.

Which solution is more concentrated?

3. Saturated: A solution is saturated if it contains as much solute as can possibly be dissolved under existing conditions of temperature and pressure. (gases only) 4. Unsaturated: Has less than the maximum amount that can be dissolved.

5. Supersaturated: Has more than the maximum amount that can be dissolved.

Saturated sol’n Supersaturated solution Unsaturated solution At 20 o C, a saturated solution contains how many grams of NaNO 3 in 100g of water? What is the solubility at 70 o C? 135 g/100 g water What kind of solution is formed when 90g NaNO 3 is dissolved in 100g water at 30 o C? unsaturated What kind of solution is formed when 120g NaNO 3 is dissolved in 100g water at 40 o C? supersaturated 90 g

The Formation of Solutions: B. How a Solution forms: 1. Process of dissolving takes place at the surface of the solute.

Dissolving an Ionic Solute

Ionic solutes break up into their ions in water

2. The interaction between the solute and solvent to allow ions to separate is called solvation. This interaction is called hydration when water is the solvent.

3. Energy is absorbed when the bonds between solute and solvent break. (endo) 4. Energy is released when bonds between solute and solvent form. (exo)

C. Solubility 1. Solubility is the amount of solute that will dissolve in a given amount of solvent at a certain temperature (pressure.)

2. Factors that affect solubility: A. Nature of Solute and Solvent: General rule: like dissolves like polar in polar nonpolar in nonpolar Example: iodine in CCl 4 (both nonpolar) salt in water (both polar – ionic)

Solubility of Polar Substances Ethanol is soluble in water because of the polar OH bond “Like Dissolves Like” Why is solid sugar soluble in water ?

Some substances are Insoluble in Water Nonpolar oil does not interact with polar water. Water-water hydrogen bonds keep the water from mixing with the nonpolar molecules.

B. Temperature: 1. As temperature increases, the solubility of gases decreases. 2. For an endothermic solid: If the temperature drops when the solute and solvent are mixed, raising the temperature will increase solubility. 3. For an exothermic solid: If the temperature rises when the solute and solvent are mixed, raising the temperature will decrease solubility.

Gases are less soluble at high temperatures than at low temperatures.

C. Pressure: 1. As pressure increases over a gas, solubility increases.

3. Factors that affect the Rate of Dissolving: A. surface area (crushing) B. stirring C. temperature D. All three of these factors affect the area over which the solvent can come into contact with the solute.

Which solution is more concentrated? In chemistry, the units used for concentration are called molarity.

Which solution has a higher concentration?

D. Molarity: (M) Ex #1) What is the molarity of a solution formed by mixing 10.0 g of sulfuric acid with enough water to make mL of solution?

Ex #2) How many grams of bromine are needed to prepare L of a M solution of bromine in water?

Ex #3) Describe how would you prepare mL of M potassium nitrate? Dissolve g KNO 3 in mL of solution.

Ex #4) What volume of M sodium hydroxide can be prepared from 4.8 g of solute?