Journal #  Assign the following characteristics to either water or rubbing alcohol a. High vapor pressure b. High polarity c. Low surface tension d. High boiling point e. Low vapor pressure f. Does not form drops g. High inward pointing force reducing surface area

Warm-up 1. How does the vapor pressure of a liquid at sea level changes when it is moved a) above sea level (Mountain) b) Below sea level (Grand Canyon) Draw 3 pictures with force diagrams at the 3 locations

Ch Solutions

Vocabulary  Solution: stable, clear homogeneous mixture  Solute: substance to be dissolved, ex. salt, sugars..but can be also a liquid or gas!!!!  Solvent: dissolving medium – liquid: water, methylene chloride, ether, rubbing alcohol…  Aqueous Solution: solution made with water as solvent ex: NaCl (aq)  Solvation: the process of how molecules dissolve  Polar: molecule with charged areas due to difference in electronegativity (Diff: above 0.4)  Non-polar: molecule with no internal charge, or evenly distributed charges (Diff=/below 0.4)

Solution Making Rule: “Like Dissolves Like”  Polar solvents dissolve polar solutes (salts in water)  Non-polar solvents dissolve non-polar solutes (oil in methylene chloride)  A non-polar solute will not dissolve in a polar solvent and vice versa!!! (oil in water)

What dissolves in water? Polar Substances: 1. Ionic compounds: salts NaCl, MgCl 2 … 2. Polar, molecular compounds: sugars What does not dissolve in water?  Non-polar compounds: oils, fats, noble gases

Non-polar solvents  Gasoline  Lighter fluid  Methylene chloride (dry cleaner)  Ether  Acetone For non-polar solutes: oil, solid fats, tar

The Solution Process - Solvation  Driven by kinetic energy 1. Water collides with ionic compounds 2. Ionic compounds break apart into their ions: NaCl → Na+ Cl- 3. Become surrounded by water molecules in opposite ways… Solvation process Solvation process

Solvation

Solvation is a power struggle A. Solvation: attraction between water and salt ions is greater than the attraction between salt ions B. Non-Solvation: attractive force between salt ions is greater than attraction between salt and water! Same for sugars or other solutes…

Electrolytes  Substances that dissociate into cation and anion in water: Salts, Acids, Bases  are able to transport electricity through an aqueous solution and complete an electric circuit  electrolyte video electrolyte video electrolyte video  Distilled water is not an electrolyte!!!

Bio: Electrolytes in the Body  Create nerve signals – action potentials  Formation of urine, sweat, saliva, tears  Formation of protective mucus coating lungs, mouth, digestive tract  Cations: Na+, K+, Mg2+, Ca2+  Anions: Cl-

Dissociation Rx – Example MgCl 2 1. It’s a reaction, needs an arrow !!!  MgCl 2 → 2. Write ions with appropriate charges  MgCl 2 → Mg 2+ + Cl - (use PT!!!) 3. Balance MgCl 2 → Mg Cl - 4. Answer sentence

Practice H 2 SO 4 Ca(OH) 2

Non-electrolytes Substances that a. do not dissolve in water: fats, oils b. dissolve, but do not produce charged particles: sugars Light bulb does not light up!

Warm-up  Write the dissociation Rx for a. K 3 P b. (NH 4 ) 2 O c. Al 2 (SO 4 ) 3

Warm-up Write the dissociation of 1. (NH 4 ) 2 (CO 3 ) 2. Al(NO 3 ) 3 3. SrCl 2