AP Chemistry Things to Know

Polyatomic ion: Ammonium

NH₄⁺

Polyatomic ion: Acetate

C₂H₃O₂^-

Polyatomic ion: Hydroxide

OH^-

Polyatomic ion: Cyanide

CN^-

Polyatomic ion: Chlorate

ClO₃^-

Polyatomic ion: Perchlorate

ClO₄^-

Polyatomic ion: Chlorite

ClO₂^-

Polyatomic ion: Hypochlorite

ClO^-

Polyatomic ion: Nitrate

NO₃^-

Polyatomic ion: Nitrite

NO₂^-

Polyatomic ion: Permanganate

MnO₄^-

Polyatomic ion: Carbonate

CO₃^2-

Polyatomic ion: Bicarbonate (Hydrogen Carbonate)

HCO₃^-

Polyatomic ion: Sulfate

SO₄^2-

Polyatomic ion: Hydrogen Sulfate

HSO₄^-

Polyatomic ion: Sulfite

SO₃^2-

Polyatomic ion: Hydrogen Sulfite

HSO₃^-

Polyatomic ion: Chromate

CrO₄^2-

Polyatomic ion: Dichromate

Cr₂O₇^2-

Polyatomic ion: Phosphate

PO₄^3-

Polyatomic ion: Hydrogen Phosphate

HPO₄^2-

Polyatomic ion: Dihydrogen Phosphate

H₂PO₄^-

Decomposition of CaCO_3(s)

CaCO_3(s) → CaO_(s) + CO_2(g)

Decomposition of KClO_3(s)

2KClO_3(s) → 2KCl_(s) + 3O_2(g)

Decomposition of Zn(OH)_2(s)

Zn(OH)_2(s) → ZnO_(s) + H₂O(l)

Decomposition of NaN_3(s)

NaN_3(s) → 2Na_(s) + 3N_2(g)

Always soluble (list 4)

Nitrates (NO₃^-), group 1 Alkali metals, Ammonium (NH₄⁺), Acetate (C₂H₃O₂^-)

Solubility of NO₃^-

Always soluble, no exceptions

Solubility of CH₃COO^-

Always soluble, no exceptions

Solubility of Cl^-

Soluble except for Ag⁺, Hg₂²⁺, Pb²⁺

Solubility of Br^-

Soluble except for Ag⁺, Hg₂²⁺, Pb²⁺

Solubility of I^-

Soluble except for Ag⁺, Hg₂²⁺, Pb²⁺

Solubility of SO₄^2-

Soluble except for Sr²⁺, Ba²⁺, Hg₂²⁺, Pb²⁺

Solubility of S^-2

Insoluble except for compounds of NH₄⁺, the alkali metal cations, and Ca²⁺, Sr²⁺, Ba²⁺

Solubility of CO₃^2-

Insoluble except for compounds of NH₄⁺ and the alkali metal cations

Solubility of PO₄^3-

Insoluble except for compounds of NH₄⁺ and the alkali metal cations

Solubility of OH^-

Compounds of the alkali metal cations and NH₄⁺, Ca²⁺, Sr²⁺, Ba²⁺

List 7 strong acids

HCl (hydrochloric acid), HI (hydroiodic acid), HBr (hydrobromic acid), HClO₃ (chloric acid), HClO₄ (perchloric acid), HNO₃(nitric acid), H₂SO₄ (sulfuric acid)

List 8 strong bases

Group 1A metal hydroxides: LiOH, NaOH, KOH, RbOH, CsOH; Heavy group 2A metal hydroxides: Ca(OH)₂, Sr(OH)₂, Ba(OH)₂

Name Type I Compounds

Metal + nonmetal -ide (ex. calcium oxide)

Name Type II Compounds

Transition metal (roman numeral (this is the oxidation #)) + nonmetal -ide

Naming Binary Molecular Compounds 1-10

Mono-, Di-, Tri-, Tetra-, Penta-, Hexa-, Hepta-, Octa-, Nona-, Deca-

Naming Acids

No Oxygen: hydro____ic acid; Polyatomic ion ends in ite: -ous acid; Polyatomic ion ends in ate: -ic acid

Density formula (PV = nRT)

D = ^PM/_RT

Percent yield formula

(^Actual/_Theoretical) * 100%

Rate of Effusion formula

^{Rate 1}/_{Rate 2} = √^{molar mass of Rate 2}/_{molar mass of Rate 1}

Aufbau Principle

Fill lower levels before filling higher levels.

Pauli Exclusion Principle

Electrons in a subshell must have opposite spins.

Hund’s Rule

Parallel spins first, then do opposite spins.

Empirical Formula + Molecular Formula

^{Molecular formula}/_{Empirical formula} = n

Isoelectronic

Having the same numbers of electrons or the same electronic structure.

Empirical formula

grams of substance → moles of substance → divide moles of substance by smallest mole → the answer = the ratio