Chemical Solutions and Chemical Reactions

Chemical Solutions and Chemical Reactions

Chpt 4 questions pg 171 -179 #15, 26, 27, 31, 37, 44, 48, 56, 66ac, 72, 79, 84, 106, 126 Due Fri 9/16

• Types of rxns• Redox, e- transfer• Net ionic equations

Water Molecule“common solvent”

Polar

Because water is polar it can dissolve ionic compounds (full charges) and polar molecules (partial charges)

Polar Water Molecules Interact with Salt Ions

Water solvates the ions, (-) charged oxygen surrounds cations, (+) charged hydrogens surround anions pull them into solution

Ethanol Molecule and Water Molecule

Demonstrates water attraction for polar molecules, also a hydrogen from another water may be attracted to theoxygen on the ethanol molecule to help solvate it.

Electrical Conductivity of aqueous solutions

The brightness of the light is related to the number of ions in solution.Strong electrolytes are totally dissociated (many ions).Weak electrolytes are slightly dissociated (few ions).Non-electrolytes (no ions) are dissolved but not ionic.

Solubility of acetic acid - weak acid & ammonia - weak base

Both are weak electrolytes (few ions in solution)

Reaction Types

• Know 5 Types by name• Precipitate reactions (formation of solid)• Acid/base reactions - neutralization

reaction (formation of water) • Oxidation/reduction reactions (electron

transfer reactions)

Net Ionic Equation• Formula Equation (complete balanced

equation)• Complete ionic equation (break down

all strong electrolytes) – Know solubility rules– aqueous solutions– strong acids and bases

• Net ionic equation – Eliminate spectator ions from equation

Solubility Rules 1. All Na+, K+, alkali metal ions and NH4

+ compounds are soluble.

2. All NO31-, C2H3O2-, HClO3

1-, and ClO41-

compounds are soluble. 3. All Cl1-, Br1-, and I1- compounds are soluble,

except those with Ag1+, Hg22+, and Pb2+

4. All SO42- compounds are soluble, except PbSO4,

BaSO4, HgSO4, CaSO4, and AgSO4.

5. Most O2-, OH1-, PO43-, CO3

2-, and S2- compounds are insoluble, except those of Na+, K+, alkali metal ions and NH4

+.

Oxidation State rules

Oxidation-reduction Process

Concentration of Solutions

• Molarity M = moles of solute / liter of solution– Molarity of each ion

• Dilutions– Moles of solute doesn’t change just

increase volume of total solution

– M1 x V1 = M2 x V2

(new volume is larger so molarity is smaller)