Equations Flashcards
(25 cards)
Topic/Equation
Formula/Expression
Moles (solid)
n = m / M
Moles (gas)
n = V / 24 (dm³) or V / 24000 (cm³) at RTP
Moles (solution)
n = c × V (in dm³)
Ideal gas equation
pV = nRT
Concentration
c = n / V (in dm³)
Titration calculation
n = c × V; use balanced equation to find unknown
Atom economy
Atom economy = (Mr of desired product / Total Mr of all products) × 100
Percentage yield
Percentage yield = (Actual yield / Theoretical yield) × 100
q = mcΔT
q = mass × specific heat capacity × temperature change
Enthalpy change
ΔH = q / n
Rate
Rate = change in concentration / time
Kc expression
Kc = [products]^coefficients / [reactants]^coefficients
pH
pH = -log[H⁺]
[H⁺] from pH
[H⁺] = 10^(-pH)
Ka
Ka = [H⁺][A⁻] / [HA]
pKa
pKa = -log(Ka)
Ka from pKa
Ka = 10^(-pKa)
Kw
Kw = [H⁺][OH⁻]
At 25°C
Kw = 1.0 × 10⁻¹⁴ mol² dm⁻⁶
Buffer pH (weak acid)
pH = pKa + log([A⁻]/[HA])
Standard cell potential
E°cell = E°(reduced) - E°(oxidised)
ΔG
ΔG = ΔH - TΔS
ΔS
ΔS = ΣS°(products) - ΣS°(reactants)
