What to memorize for the AP Chemistry Exam

everything I tried to have memorized by the ap chemistry exam.

Percent Error =

(|calculated answer - correct answer|/correct answer) x 100

Ammonium:

NH4^+

Bromate:

BrO3^-

Perchlorate:

ClO4^-

Chlorate:

ClO3^-

Chlorite:

ClO2^-

Hypochlorite:

ClO^-

Cyanide:

CN^-

Carbonate:

CO3^2-

Chromate:

CrO4^2-

Sulfate:

SO4^2-

Oxalate:

C2O4^2-

Acetate:

C2H3O2^-

Hydroxide:

OH^-

Iodate:

IO3^-

Periodate:

IO4^-

Nitrate:

NO3^-

Nitrite:

NO2^-

Permanganate:

MnO4^-

Peroxide:

O2^2-

Dichromate:

Cr2O7^2-

Sulfite:

SO3^2-

Phosphate:

PO4^3-

First Important Solubility Rule:

Compounds containing Na^+, K^+, or NH4^+ ions are ALWAYS soluble in water.

Second Important Solubility Rule:

Compounds containing NO3^- ions are always soluble in water.

Potential Difference, or Voltage, of a Galvanic Cell (must be +): Ecell =

Ecathode - Eanode

Reduction:

• takes place at the cathode

• is gaining e-

Oxidation:

• takes place at the anode

• is losing e-

A metallic cathode will:

always increase in mass.

Electrons move through the wire from:

anode (decreases in mass) to cathode (increases in mass).

Salt Bridge:

• anions will flow to the anode

• cations will flow to the cathode

Change in Enthalpy (heat):

ΔH

Change in Entropy (disorder):

ΔS

Difference in Gibbs Free Energy (ΔG) =

ΔH - T(ΔS)

-RTln(K)

Thermodynamically favored at all temperatures when:

ΔH is negative and ΔS is positive.

Never thermodynamically favored at any condition when:

ΔH is positive and ΔS is negative.

Thermodynamically favored at higher temperatures when:

ΔH and ΔS are both positive.

Thermodynamically favored at lower temperatures when:

ΔH and ΔS are both negative.

Zeroth Order:

[A]t - [A]0 = kt

First Order:

ln[A]t - ln[A]0 = kt

Second Order:

1/[A]t - 1/[A]0 = kt

First Order Half-Life:

t1/2 = 0.693/k

Coulomb’s Law:

F = k(q1q2/d²)

F:

Attractive force between the two charged particles.

d²:

Distance between the two charged particles.

q1q2:

Magnitude of charge of each of the two charged particles.

As the magnitude of the charge of the particles goes up:

so does the attractive force between the particles.

As the distance between two charged particles goes down:

their attractive force goes up.

Formal Charge =

# valence e- an atoms has - (# unshared e- + # individual e- bonds assigned to that atom)

Steric Number =

# atoms that central atom is touching - # unshared e- pairs on that central atom

Steric Number

2

3

4

Hybridization

sp

sp²

sp³

Boyle’s Law (inverse relationship):

P1V1 = P2V2

Charles’ Law (direct relationship):

V1/T1 = V2/T2

Gay-Lussac’s Law (direct relationship):

P1/T1 = P2/T2

The Dilution Equation:

M1V1 = M2V2

Percent Yield =

(Actual Yield/Theoretical Yield) x 100

ΔH =

ΣHbonds broken - ΣHbonds formed

Percent Dissociation of a Weak Acid =

([H3O^+]equilibrium/[HA]initial) x 100

Percent Dissociation of a Weak Base =

([OH^-]equilibrium/[B]initial) x 100

The Titration Equation:

M_AV_A = M_BV_B

Average Atomic Mass:

(mass of isotope)(% abundance)

Overall = avg.1 + avg.2 + …

Atomic radius is greatest at:

the bottom left of the periodic table.

Cations tend to be:

smaller than anions.

First ionization energy is greatest at:

the top right of the periodic table.

Complete combustion means products are:

CO2 and H2O.

rate =

k[A]^m[B]^n

Elements in natural state will have an enthalpy of:

zero.

Kc =

[products]^m/[reactants]^n

Kp =

Pproducts^m/Preactants^n

If K<1:

more reactants; products favored.

If Q>K:

more products; reactants favored; pressure of products will decrease.

The Six Strong Acids:

HCl, HBr, HI, HNO3, H2SO4, HClO4

The Eight Strong Bases:

LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

• multiply concentration by 2 for Group 2 hydroxides

At the half-equivalence point:

• pH = pKa

• [HA] = [A^-]

At the equivalence point:

the acid is all gone.

Materials at higher temperatures or with more molecules have:

more entropy than those with lower/less.

Universal Gas Constant (R) =

0.0821 (L x atm/ mol x K)

Ideal Gas Costant (R) =

8.314 J/mol x K