This chapter covers the principles of chemical equilibrium, including its significance in biological and environmental processes. It emphasizes understanding dynamic equilibrium, the equilibrium constant, and the factors affecting equilibrium states.
Equilibrium – Formula & Equation Sheet
Essential formulas and equations from Chemistry Part - I, tailored for Class 11 in Chemistry.
This one-pager compiles key formulas and equations from the Equilibrium chapter of Chemistry Part - I. Ideal for exam prep, quick reference, and solving time-bound numerical problems accurately.
Key concepts & formulas
Essential formulas, key terms, and important concepts for quick reference and revision.
Formulas
K_c = [C]^c [D]^d / [A]^a [B]^b
K_c is the equilibrium constant for a reaction at a given temperature, where [A], [B], [C], and [D] are the equilibrium concentrations of reactants and products, respectively.
K_p = K_c (RT)^(Δn)
K_p is the equilibrium constant expressed in terms of partial pressures where Δn is the change in the number of moles of gas.
Q_c = [C]^c [D]^d / [A]^a [B]^b
Q_c is the reaction quotient, allowing us to determine the direction of the reaction relative to equilibrium.
ΔG = ΔG° + RT ln Q
This equation relates Gibbs free energy at non-equilibrium conditions (ΔG) to the standard Gibbs free energy change (ΔG°) and the reaction quotient (Q).
pH = -log[H^+]
pH is the negative logarithm of the hydrogen ion concentration, providing a measure of acidity.
K_w = [H^+][OH^-]
K_w is the ionic product of water at a given temperature, where [H^+] and [OH^-] are the concentrations of hydrogen and hydroxide ions, respectively.
K_a = [H^+][A^-] / [HA]
K_a is the ionization constant for a weak acid, showing the equilibrium between the acid (HA), hydrogen ions (H^+), and its conjugate base (A^-).
K_b = [B^+][OH^-] / [BOH]
K_b is the ionization constant for a weak base, representing the equilibrium between the base (BOH), its conjugate acid (B^+), and hydroxide ions (OH^-).
K_sp = [A^+]^m [B^-] ^n
K_sp is the solubility product constant for a sparingly soluble salt, where A and B are ions from the salt with stoichiometric coefficients m and n.
pH = pK_a + log([A^-]/[HA])
This is the Henderson-Hasselbalch equation for buffering solutions, which relates pH, pK_a, and the concentrations of a weak acid and its conjugate base.
Equations
H_2O(l) ⇌ H^+(aq) + OH^-(aq)
This represents the autoionization of water, resulting in equal concentrations of hydrogen and hydroxide ions.
K_sp = [B^2+][X^2-]
For the dissolution of salt BX to give its ions, the solubility product constant (K_sp) is dependent on the concentrations of the ions in solution.
A + B ⇌ C + D
This is a general representation of a reversible reaction reaching dynamic equilibrium.
ΔG° = -RT ln K
This relationship indicates how Gibbs free energy change (ΔG°) is related to the equilibrium constant (K) at standard conditions.
K_p = K_c (RT)^Δn
This shows how to convert between K_c and K_p when dealing with gaseous reactions.
Fe^{3+}(aq) + SCN^{-}(aq) ⇌ [Fe(SCN)^{2+}](aq)
This equilibrium demonstrates the formation of a complex ion, crucial for analytical chemistry.
2 NOCl(g) ⇌ 2 NO(g) + Cl_2(g)
This portrays the equilibrium reaction of the decomposition of nitrosyl chloride.
pK_w = pH + pOH
This relationship helps determine the pH and pOH of a solution at any given temperature.
CH_3COOH(aq) ⇌ H^+(aq) + CH_3COO^-(aq)
This represents the dissociation of acetic acid into hydrogen ions and acetate ions.
NH_4^+(aq) + OH^-(aq) ⇌ NH_3(aq) + H_2O(l)
This equilibrium illustrates the hydrolysis reaction involving ammonium ions.
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