Reaction Calculators: Chemical Equations and Redox

Work through chemical reactions with calculators for balancing equations, checking redox reactions, and exploring how temperature affects reaction rates. The Chemical Equation Balancer helps you find coefficients that conserve atoms, while Balancing Redox Reactions handles electron transfer. Use the Arrhenius Equation calculator to examine the relationship between temperature and reaction rate, or Estimation of Calcium for calcium-related calculations. These tools are useful for chemistry students, teachers, and laboratory users checking their work.

Balancing Redox Reactions

Balance a redox equation by entering its reactants and products, including ionic charges. The calculator finds coefficients that conserve both atoms and charge.

Solubility Product

Calculate the solubility product (Ksp) of a sparingly soluble salt from its molar solubility. Enter the solubility, its unit, and the cation and anion coefficients from the formula AaBb.

Estimation of Calcium

Enter the volume and normality of KMnO₄ used in the titration and the sample weight. The calculator returns a value labeled calcium percentage; check the formula against your laboratory method before interpreting it as a true calcium content.

TLC Rf

Enter the distance your TLC spot traveled and the distance the solvent front traveled, and this calculator returns the retention factor Rf with an interpretation of the separation quality.

Chemical Equation Balancer

Enter a chemical equation using = between reactants and products to find balancing coefficients. The calculator shows a balanced equation when it can process the formulas.

Atom Economy

Enter the coefficients and molar masses of all reactants in the balanced equation plus the coefficient and molar mass of your desired product to get the atom economy, the by-product mass per 100 g of reactants, and an interpretation.

Antoine Equation

Calculate the vapor pressure of a pure liquid at a given temperature, or the boiling temperature at a given pressure, using Antoine coefficients A, B and C. Works with mmHg, kPa, bar and other pressure units.

Arrhenius Equation

Calculate a reaction rate constant with the Arrhenius equation. Enter the frequency factor, activation energy in kJ/mol, and temperature in kelvin.

Precipitation Prediction

Enter the cation and anion concentrations, their stoichiometric exponents, and the solubility product Ksp to find out whether a precipitate forms when two solutions are mixed. The calculator compares the ion product Qsp with Ksp and predicts precipitation instantly.

Chromatography Resolution

Enter the retention times and widths of two chromatographic peaks to calculate their resolution (Rs) and find out whether they are baseline-separated. Supports widths measured at the baseline or at half height.

Chemical Oxygen Demand

Calculate the chemical oxygen demand (COD) of a water sample from a dichromate back-titration. Enter the blank and sample FAS titration volumes, the titrant normality, and the sample volume to get the result in mg/L as O₂.

Langmuir Adsorption Isotherm

Calculate fractional surface coverage θ and adsorbed amount q from the Langmuir isotherm. Enter the equilibrium concentration or pressure, the affinity constant KL, and optionally the maximum capacity qmax.

Kirchhoff's Law of Thermochemistry

Convert a reaction enthalpy from one temperature to another using Kirchhoff's law. Enter the known enthalpy at a reference temperature, the target temperature, and the summed heat capacities of reactants and products.

Standard Cell Potential

Enter the standard reduction potentials of the cathode and anode to get the standard cell potential E°cell, the spontaneity verdict, and the free energy change ΔG° per mole of electrons.

Calorimetry

Calculate the heat absorbed or released by a substance using Q = mcΔT. Enter the mass, specific heat capacity and the initial and final temperatures to get Q in joules, kilojoules and kilocalories.

Hess's Law

Calculate the enthalpy change of any reaction using Hess's law: combine known reactions with multipliers, or build the target reaction from standard formation enthalpies. Enter your values and get the result in kJ/mol and kcal/mol.

Reaction Half-Life

Calculate the half-life of a zero-, first- or second-order chemical reaction from the rate constant k and, where needed, the initial concentration. Results are shown in seconds and in your chosen time unit.

Electrochemical Equilibrium Constant

Enter the standard cell potential E°cell, the number of electrons transferred n, and the temperature to find the equilibrium constant K of a redox reaction from ΔG° = −nFE° = −RT ln K.

Van 't Hoff Equation

This calculator uses the Van 't Hoff equation to predict how an equilibrium constant changes with temperature. Enter K at a reference temperature, the standard reaction enthalpy, and the two temperatures to get K at the new temperature, the change factor, and ΔG°.

Reaction Order from Initial Rates

Enter the concentration and initial rate measured in each experiment, and this calculator determines the reaction order n, the rate constant k, and the full rate law using the method of initial rates.

Equilibrium Constant

Calculate the equilibrium constant Kc from the equilibrium concentrations of reactants and products. Enter the stoichiometric coefficients and concentrations from your balanced equation to get Kc, 1/Kc, and whether the reaction is product- or reactant-favoured.

Reaction Rate Law

Calculate the instantaneous reaction rate from the rate law v = k[A]^a[B]^b… Enter the rate constant, the concentration and order of each reactant, and get the rate, overall order and correct unit of k.

Nernst Equation

Calculate the cell potential of an electrochemical cell under nonstandard conditions using the Nernst equation. Enter the standard potential E°, temperature, electrons transferred n, and reaction quotient Q.

Clausius–Clapeyron

Estimate the vapor pressure of a liquid at any temperature from one known pressure–temperature pair and the enthalpy of vaporization, using the integrated Clausius–Clapeyron equation. Enter the known conditions, the target temperature, and ΔHvap.

Electrolysis

Calculate the mass deposited or produced in an electrolysis cell using Faraday's law. Enter the current, time, molar mass, and electrons transferred per formula unit to get charge, moles, and deposited mass.

Gibbs Free Energy

Calculate the Gibbs free energy change (ΔG) from enthalpy (ΔH), entropy (ΔS), and temperature, and instantly see whether the reaction is spontaneous under those conditions.

Kp to Kc

Convert an equilibrium constant between its pressure-based form (Kp) and concentration-based form (Kc). Enter the known constant, the temperature, and the change in moles of gas to get the result instantly.

pH

Calculate the pH and pOH of a solution from its hydrogen ion (H⁺) or hydroxide ion (OH⁻) concentration. Enter the molar concentration and an optional temperature to get pH, pOH and pKw.

Radioactive Decay

Calculate how much of a radioactive isotope remains after any time. Enter the initial amount or activity, the half-life, and the elapsed time to get the remaining amount, decay constant, and number of half-lives.

Standard Entropy of Reaction

Calculate the standard entropy of reaction ΔS° from tabulated standard molar entropies. Enter the stoichiometric coefficient and S° of each reactant and product, pick a unit, and get ΔS° with a full breakdown.

Titration

Calculate the unknown concentration of an acid or base from titration data. Enter the concentration and volume of the known solution, the volume of the unknown solution, and the reaction ratio.