AP chemistry prep

Polyatomic ions

Ammonium

NH4+ charge +1

Acetate

C2H3O2- or CH3COO-, charge -1

Nitrate

NO3-, charge -1

Nitrite

NO2-, charge -1

Hydroxide

OH-, charge -1

Bicarbonate

HCO3-, charge -1

Carbonate

CO3 2-, charge -2

Sulfate

SO4 2-, charge -2

Sulfite

SO3 2-, charge -2

Phosphate

PO4 3-, charge -3

Chlorate

ClO3-, charge -1

Perchlorate

ClO4-, charge -1

Strong acids

Hydrochloric acid

HCl, strong acid

Hydrobromic acid

HBr, strong acid

Hydroiodic acid

HI, strong acid

Nitric acid

HNO3, strong acid

Sulfuric acid

H2SO4, strong acid (first H+ dissociates fully)

Perchloric acid

HClO4, strong acid

Strong bases

Sodium hydroxide

NaOH, strong base

Potassium hydroxide

KOH, strong base

Lithium hydroxide

LiOH, strong base

Calcium hydroxide

Ca(OH)2, strong base

Strontium hydroxide

Sr(OH)2, strong base

Barium hydroxide

Ba(OH)2, strong base

Basic solubility rules

Always soluble

Compounds with Group 1 cations and ammonium

Always soluble

Compounds with nitrate, acetate, chlorate ions

Mostly insoluble

Carbonates, phosphates, sulfides (except Group 1 and ammonium)

Halides soluble

Chloride, bromide, iodide soluble except with Ag+, Pb2+, Hg2^2+

Sulfate soluble

Except with Ba2+, Sr2+, Pb2+, Ca2+

Periodic trends

Atomic radius

Decreases across a period, increases down a group

Ionization energy

Increases across a period, decreases down a group

Electronegativity

Increases across a period, decreases down a group

Metallic character

Decreases across a period, increases down a group

Common transition metal charges

Iron (II)

Fe2+ charge +2

Iron (III)

Fe3+ charge +3

Copper (I)

Cu+ charge +1

Copper (II)

Cu2+ charge +2

Lead (II)

Pb2+ charge +2

Lead (IV)

Pb4+ charge +4

Tin (II)

Sn2+ charge +2

Tin (IV)

Sn4+ charge +4

Chromium (III)

Cr3+ charge +3

Manganese (II)

Mn2+ charge +2

Naming conventions

-ate ending

Oxyanion with more oxygen atoms (e.g., nitrate NO3-)

-ite ending

Oxyanion with fewer oxygen atoms (e.g., nitrite NO2-)

Per-…-ate

Most oxygen (e.g., perchlorate ClO4-)

Hypo-…-ite

Least oxygen (e.g., hypochlorite ClO-)

Roman numerals

Used to indicate charge on transition metals (e.g., Iron (III))

Rate law

rate = k [A]^m [B]^n

“The rate equals the rate constant k times the concentration of A to the m power times the concentration of B to the n power.”

What it means:

How fast the reaction goes depends on how much reactant you have and what the reaction order is for each one.

Coulomb’s Law

F = k_e (q₁ q₂) / r²

“The force equals the electrostatic constant k e times the product of the two charges divided by the distance squared.”

What it means:

This tells you how strongly two charged particles attract or repel each other based on their charges and distance apart.

Percent yield

% yield = (actual / theoretical) × 100%

Formula:

percent yield = (actual / theoretical) × 100%

How to say it:

“Percent yield equals the actual yield divided by the theoretical yield times one hundred percent.”

What it means:

This shows how efficient your reaction was compared to the maximum possible.

percent error

% error = ((actual – theoretical) / theoretical) × 100%

How to say it:

“Percent error equals the difference between actual and theoretical divided by theoretical times one hundred percent.”

What it means:

This measures how far off your experimental result was from the accepted value

Molarity

M = moles solute / liters solution

“Molarity equals moles of solute divided by liters of solution.”

What it means:

This tells you how concentrated your solution is.