Unit 4: Reactions & Redox

Phase Change
(physical change)

Overcome IMF's

Chemical Change

Involve the breaking/making of intramolecular bonds OR the movement of electrons (redox)

%Yield

(experimental/theoretical)

%Error

(experimental - theoretical)/theoretical

Limiting Reactant

Determines the amount of product for a reaction

RICE Box

Good for Stoich/LR problems, never use grams; use moles

Evidence of a Chemical Reaction

The formation of a precipitate, change in energy with light or heat, a color change, formation of a gas, observation of electrical current.

Combustion Reactions

Make CO2 and H2O

Combustion Analysis

Helps identify the formula of the hydrocarbon in a combustion reaction

Strong Acids

HNO3, H2SO4, HClO4, and HBr, HI, HCl... "NO SO ClO 3, 4, 4 and BrICl"

Strong Bases

Group 1 hydroxides Group 2 hydroxides *Some Group II hydroxides are only slightly soluble, but whatever dissolves can completely ionize.

Weak Acids and Bases

Don't dissociate and are not ever spectators to be eliminated; they appear as molecules in the Net Ionic Equation (eg - acetic acid, HC2H3O2 aka CH3COOH)

Donate [H+]

Acids

Recieve [H+]

Bases

OIL RIG/LEO GER

Oxidation Is Loss, Reduction Is Gain/Lose Electrons Oxidize, Gain Electrons Reduction

Reducing Agent

The atom that gets oxidized in part of a compound

Oxidation

makes an atom MORE POSITIVE

Reduction

makes an atom MORE NEGATIVE (lower on the number line)

Stoichiometric equivalence

The reactants are used up precisely leaving NO excess of either one. The moles used of each are in proportion with the coefficients of the balanced chemical equation. The concept is important in titrations.

SOLUBLE compounds

All group 1, ammoniums, nitrates, chlorates, hydrogen carbonates; most halides (not Ag+, Pb+2, Hg2+2), most sulfates (not Ag+, Sr+2, Pb+2, Ca+2)

INSOLUBLE compounds

Hydroxides (except group 1, ammonium, Ca+2, Sr+2, Ba+2); carbonates, phosphates, chromates, sulfides (except group 1, ammonium, & the sulfides of group 2)

Solubility

Can be used to determine a solution's solute identity. Being aware of some of the reactions/colors of solutions & precipitates may help "unlock" a question for you.

You may not have to predict redox reaction products but...

You may need to know how many electrons are moving in a reduction or oxidation process.