AP chem: equations to memorize

Mole fraction

N_component / N_total

Percentage yield

(amount of product obtained / amount of product expected) x 100%

Percentage purity (by mass)

(mass of pure chemical / mass of impure sample) x 100%

Boyle’s law

P₁V₁ = P₂V₂

Gay-Lussac’s law

P₁T₁ = P₂T₂

Charles’s law

V₁T₁ = V₂T₂

Avogadro law

(N₁ / V₁) = (N₂ / V₂)

Graham’s law (effusion and diffusion)

Option one (distance travelled): √ (m₂ / m₁)

Option two (rate of effusion): √ (M₂ / M₁)

*gas 1 will diffuse (answer) for every 1m that gas 2 diffuses

Deviation from ideal gas law

(P + (an² / V²)) (V - nb ) = nRT

*a = attraction (adjusts for lost pressure and fewer collisions)

*b = volume of particles (adjusts for particle volume and repulsions; V_measured > V_ideal)

Dilution calculations

C₁V₁ = C₂V₂

3 forms of spectroscopy

Microwave radiation = molecules rotate

Infrared radiation = molecules vibrate

UV/Visible radiation =electrons change energy levels

Calculating reaction rates

(∆volume OR ∆mass OR ∆concentration) / ∆time

Rate law

k [A]^m [B]ⁿ

Law of Conservation of Energy

∆E_universe = ∆E_system + ∆E_surroundings = 0

Total energy change formula

Total energy change = enthalpy change + work

∆E = Q + w

PV work

Work = - (P) (∆V)

Bond enthalpies

∆H_reaction = ∑ nB.E. _{(bonds broken)} - ∑ nB.E._{(bonds formed)}

Equilibrium equation

rate_fwd = rate_rev

Reaction quotient

Q = [C]^c [D]^d / [A]^a [B]^b

Q = K_c → at equilibrium

Q < K_c → reaction going forward, products being formed

Q > K_c → reaction going backward, reactants being formed