Chemistry — Formula Sheet
Key formulas for TS Inter 1st Year Chemistry — Atomic Structure, Gases, Stoichiometry, Thermodynamics, and Equilibrium. Based on TGBIE Annual Plan 2025-26.
Ch. 1 Atomic Structure
- 1Bohr radius: aₙ = n²a₀/Z where a₀ = 0.529 Å
- 2Energy of nth orbit: Eₙ = −13.6Z²/n² eV
- 3Wave number: ν̄ = RH(1/n₁² − 1/n₂²); RH = 1.097 × 10⁷ m⁻¹
- 4de Broglie wavelength: λ = h/mv
- 5Heisenberg: Δx · Δp ≥ h/(4π)
- 6Quantum numbers: n (principal), l (azimuthal, 0 to n−1), m (magnetic, −l to +l), s (spin, ±½)
Ch. 4 States of Matter
- 1Boyle's law: P₁V₁ = P₂V₂ (constant T, n)
- 2Charles's law: V₁/T₁ = V₂/T₂ (constant P, n)
- 3Ideal gas equation: PV = nRT; R = 8.314 J mol⁻¹ K⁻¹
- 4Graham's law: r₁/r₂ = √(M₂/M₁)
- 5Dalton's partial pressure: P_total = P_A + P_B + ...
- 6van der Waals: (P + an²/V²)(V − nb) = nRT
- 7KE per mole = (3/2)RT; v_rms = √(3RT/M)
Ch. 5 Stoichiometry
- 1Moles: n = mass/molar mass; n = volume(L)/22.4 (at STP)
- 2Molarity: M = moles of solute / volume of solution (L)
- 3Molality: m = moles of solute / mass of solvent (kg)
- 4Mole fraction: χ_A = n_A / (n_A + n_B)
- 5% composition: (mass of element / molar mass) × 100
Ch. 6 Thermodynamics
- 11st law: ΔU = q + w; w = −PΔV for expansion
- 2Enthalpy: H = U + PV; ΔH = ΔU + ΔnRT (for gases)
- 3Hess's law: ΔH_rxn = Σ ΔH_f(products) − Σ ΔH_f(reactants)
- 4Gibbs energy: ΔG = ΔH − TΔS
- 5Spontaneity: ΔG < 0 (spontaneous); ΔG = 0 (equilibrium); ΔG > 0 (non-spontaneous)
- 6ΔG° = −RT·lnK; K = e^(−ΔG°/RT)
Ch. 7 Chemical Equilibrium
- 1Kc = [products]^stoich / [reactants]^stoich
- 2Kp = Kc(RT)^Δn where Δn = moles of gaseous products − reactants
- 3Degree of dissociation α: from Kc expression
- 4Henderson-Hasselbalch: pH = pKa + log([A⁻]/[HA])
- 5pH = −log[H⁺]; pOH = −log[OH⁻]; pH + pOH = 14 at 25°C
- 6Kw = [H⁺][OH⁻] = 10⁻¹⁴ at 25°C
- 7Ksp = [A^m⁺]^a[B^n⁻]^b for sparingly soluble salt AₐBᵦ