Chemistry

  • Gibbs Free Energy from Equilibrium Constant Calculator
    Calculate standard Gibbs free energy change ΔG° from the equilibrium constant K and temperature using ΔG° = −RT ln K. Free, instant results in kJ/mol.
  • Bond Enthalpy Calculator
    Calculate the enthalpy change (ΔH) of a reaction from bond energies: ΔH = sum of bonds broken minus sum of bonds formed. Free chemistry tool.
  • Enthalpy of Reaction Calculator (Hess's Law)
    Calculate the enthalpy of reaction (ΔH) using Hess's Law from the standard enthalpies of formation of products and reactants. Free and instant.
  • First-Order Reaction Half-Life Calculator
    Calculate the half-life of a first-order reaction from its rate constant k using t½ = 0.693 / k. Fast, accurate chemistry kinetics tool.
  • pH Calculator for Strong & Weak Acids and Bases
    Calculate the pH and pOH of strong and weak acid or base solutions from concentration and Ka/Kb. Free chemistry pH calculator with worked examples.
  • Ka, Kb, pKa, pKb Calculator
    Convert between Ka, Kb, pKa and pKb instantly. Enter any one value and get the other three using pKa = -log10(Ka) and pKa + pKb = 14 at 25°C.
  • Van't Hoff Factor Calculator
    Calculate the Van't Hoff factor (i) from observed freezing point depression, the cryoscopic constant Kf, and molality. Free chemistry tool with formula.
  • Freezing Point Depression Calculator
    Calculate freezing point depression (ΔTf = i·Kf·m) from the van 't Hoff factor, cryoscopic constant, and molality, plus the new freezing point.
  • pOH Calculator
    Free pOH calculator: find pOH from hydroxide ion concentration [OH⁻] or from pH using pOH = -log10[OH⁻] and pH + pOH = 14.
  • Gay-Lussac's Law Calculator
    Free Gay-Lussac's Law calculator. Solve P1/T1 = P2/T2 for pressure or temperature at constant volume. Enter three values to find the fourth instantly.
  • Significant Figures Arithmetic Calculator
    Add, subtract, multiply or divide two numbers and round to the correct significant figures. Supports scientific and e-notation with full sig-fig rules.
  • Ideal Gas Law Calculator (PV = nRT)
    Solve the ideal gas law PV = nRT for pressure, volume, moles, or temperature. Enter any three values with flexible units (atm, L, mol, K) to find the fourth.
  • Molecular Weight Calculator
    Compute molecular/formula weight in g/mol from any chemical formula like H2O or AgS2O3, with a per-element atomic-weight and contribution breakdown.
  • Absolute Uncertainty Calculator
    Calculate absolute uncertainty from a measured value and its relative (percentage) uncertainty. Get the ± value and the measurement range instantly.
  • Radioactivity Unit Conversion Calculator
    Convert radioactivity between Becquerel (Bq) and Curie (Ci) units. Enter an activity value and see all 12 SI and Curie-family units at once. 1 Ci = 3.7e10 Bq.
  • Radiation Exposure Unit Conversion Calculator
    Convert radiation exposure between Roentgen (R, mR, uR) and Coulomb per kilogram (C/kg, mC/kg, uC/kg) using the exact 1 R = 2.58e-4 C/kg definition.
  • Absorbed Dose Unit Converter (Gray / Rad)
    Convert absorbed radiation dose between gray (Gy), its SI prefixes, rad and millirad. 1 Gy = 100 rad = 1 J/kg. Instant full conversion table.
  • Wavenumber Calculator
    Calculate wavenumber from wavelength. Angular k = 2π/λ (rad/m) or spectroscopic ν̃ = 1/λ (1/m and 1/cm). Supports nm, µm, mm, cm, m.
  • Wavelength to Frequency Calculator
    Convert wavelength to frequency instantly using f = c / λ with the speed of light c = 2.998×10⁸ m/s. Supports nm, µm, mm, cm, and m units.
  • Thermal Energy Calculator
    Calculate thermal energy (heat) Q with the formula Q = m·c·ΔT. Enter mass, specific heat, and temperature change to get energy in joules and kJ.
  • Specific Heat Calculator
    Calculate specific heat capacity from heat energy, mass, and temperature change using c = Q / (m·ΔT). Fast, accurate physics tool with worked example.
  • Root Mean Square Velocity Calculator
    Calculate the root mean square (RMS) velocity of gas molecules from temperature and molar mass using v_rms = sqrt(3RT/M). Fast, accurate, free.
  • Sensible Heat Calculator
    Calculate sensible heat with Q = m·c·ΔT. Enter mass, specific heat, and temperature change to find energy in joules and kilojoules.
  • Specific Gas Constant Calculator
    Calculate the specific gas constant Rspecific = R/M from molar mass. Universal R = 8.314 J/mol·K. Instant J/(kg·K) result with worked example.

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