Chemistry Tools
Browse all available chemistry tools.
Available tools
- Absorbance From Transmittance Convert percent transmittance to absorbance.
- Absorptivity From Slope Compute molar absorptivity from a Beer-Lambert calibration slope by dividing the slope by the optical path length.
- Acentric Factor Lookup Look up acentric factor omega of a common substance.
- Acid Dissociation Fraction Calculator Solve the exact dissociation fraction α of a weak acid from Ka and concentration using Cα² + Ka·α − Ka = 0.
- Acidity Calculator Calculate acidity as calcium carbonate equivalent from base titrant volume, normality, and sample volume.
- Activation Energy Two-Temperature Compute activation energy in J/mol from rate constants at two temperatures as R times ln(k2/k1) over one over T1 minus one over T2.
- Activity Calculator Compute thermodynamic activity a = gamma * concentration.
- Activity Coefficient From Gamma Input Compute the ionic activity as the activity coefficient times the molar concentration.
- Activity Decay Calculator Compute the radioactive activity after a time as A = A₀·e^(−λt) with λ = ln2/t½.
- Activity From Fugacity Compute the thermodynamic activity as the ratio of fugacity to the standard pressure of one bar.
- Alkalinity Calculator Calculate alkalinity as calcium carbonate equivalent from acid titrant volume, normality, and sample volume.
- Alpha Decay Energy Calculator Calculate the Q value of alpha decay from parent and daughter nuclear masses.
- Altitude From Pressure Invert the barometric formula to estimate altitude from measured atmospheric pressure.
- Ampholyte pH Calculator Compute ampholyte pH = 0.5*(pKa1+pKa2).
- Analyte Mass From Precipitate Compute analyte mass from precipitate mass by applying the gravimetric factor.
- Analytical Detection Limit Estimate a detection limit from response standard deviation and calibration slope using the stated 3.3σ/slope convention. This is one common calibration-based estimate, not a universal regulatory limit.
- Analytical Dilution Correction Calculator Correct a diluted analytical concentration using the aliquot and final solution volumes.
- Analytical Quantification Limit Estimate a quantification limit from response standard deviation and calibration slope using the stated 10σ/slope convention. Confirm the method-specific definition before reporting an official LOQ.
- Analytical Relative Standard Deviation Calculate relative standard deviation from a supplied sample standard deviation and mean: RSD%=100s/|mean|. The mean cannot be zero; this is a precision measure, not an accuracy estimate.
- Analytical Spike Recovery Calculate percent recovery as (measured spiked result − unspiked result)/known spike amount ×100. All three quantities must use the same unit; values outside 0–100% can reveal matrix effects or measurement problems.
- Arrhenius Pre-exponential Factor Calculator Solve for A = k * exp(Ea/RT).
- Arrhenius Rate Constant Compute the Arrhenius rate constant as the frequency factor times exp of minus activation energy over R times temperature.
- Atom Economy Calculator Compute atom economy as desired product molar mass over total products molar mass times 100.
- Atomic Radius Lookup Look up a calculated atomic radius for an element in picometers.
- Average Speed Gas Compute the Maxwell-Boltzmann mean molecular speed of a gas from temperature and molar mass.
- Back Titration Calculator Compute analyte moles from excess titrant back-titration.
- Barometric Pressure Estimate atmospheric pressure at altitude from temperature using the barometric formula.
- Base Dissociation Fraction Calculator Solve the exact dissociation fraction α of a weak base from Kb and concentration using Cα² + Kb·α − Kb = 0.
- Battery Capacity Calculator Compute battery capacity in ampere-hours.
- BDE Average Compute the average bond dissociation enthalpy by dividing a total bond energy over the number of bonds.
- Beer-Lambert Absorbance Compute absorbance from molar absorptivity, concentration, and path length.
- BET Monolayer Capacity Derive BET monolayer capacity and BET C constant from the slope and intercept of a correctly prepared BET linear plot. Both must be positive for this form; choosing a valid relative-pressure range remains the analyst's responsibility.
- Beta Decay Energy Calculator Calculate beta-minus or beta-plus decay Q value from parent and daughter atomic masses.
- Binding Energy Per Nucleon Calculator Convert a mass defect into total binding energy and divide by the nucleon count using 931.494 MeV per atomic mass unit.
- BOD Calculator Calculate biochemical oxygen demand from dissolved-oxygen depletion and a dilution factor.
- Bohr Radius Calculator Calculate the Bohr-model radius of a hydrogen-like atom or ion at a specified principal quantum number.
- Boiling Point Clausius-Clapeyron Calculator Solve for T2 from the Clausius-Clapeyron equation.
- Boiling Point Elevation Estimate boiling point elevation from molality, the ebullioscopic constant, and the van 't Hoff factor.
- Bomb Calorimeter Energy Calculator Compute heat of combustion from bomb calorimeter as q = C_cal * dT.
- Bond Energy Calculator Compute total bond energy from number of bonds and energy per bond.
- Bond Enthalpy Calculator Calculate bond enthalpy calculator.
- Bond Length From Order Calculator Estimate bond length from bond order using empirical scaling of the single-bond reference length.
- Bond Order Calculator Compute molecular orbital bond order as (bonding electrons − antibonding electrons) / 2.
- Bond Polarity Calculator Compute electronegativity difference between two bonded atoms.
- Born-Haber Lattice Energy Calculator Solve the signed lattice formation enthalpy from a Born-Haber cycle, using a signed electron-attachment enthalpy (normally negative).
- Boyle Temperature Calculator Compute Boyle temperature T_B = a/(R*b).
- Boyle's Law Calculator Compute the final pressure of a gas at constant temperature as initial pressure times initial volume over final volume.
- Bragg Angle Calculator Solve Bragg's law n*lambda = 2*d*sin(theta) for the diffraction angle theta in degrees.
- Bromothymol Blue Range Checker Check whether a pH falls within bromothymol blue range 6.0-7.6.
- Buffer Capacity Estimate Estimate buffer capacity from total buffer concentration, Ka, and hydrogen ion concentration.
- Buffer Dilution pH Calculator Buffer pH remains unchanged upon dilution because Henderson-Hasselbalch ratio is preserved.
- Buffer Effective Checker Check whether a pH lies within the effective buffering range of pKa ± 1.
- Buffer pH After Addition Compute the buffer pH after adding strong base as pKa plus log10 of conjugate base over remaining weak acid.
- Buffer Range Calculator Compute the effective buffering range as pKa ± 1 around a weak acid's pKa.
- Buffer Ratio Calculator Apply the Henderson-Hasselbalch relation to compute the conjugate-base-to-acid ratio [A⁻]/[HA] = 10^(pH−pKa).
- Calibration Intercept Compute the calibration curve intercept from the low calibration point and the slope.
- Calibration Slope Compute the calibration curve slope from two concentration and response pairs.
- Calorimeter Constant Calculator Compute calorimeter constant C_cal = q / dT.
- Calorimetry Heat Exchange Calculator Calculate calorimetry heat exchange calculator.
- Capacity Factor k' Compute the capacity factor k-prime as adjusted retention time over dead time for a retained analyte.
- Capacity Ratio k2/k1 Compute the chromatographic capacity ratio from two adjusted capacity factors, k2 divided by k1.
- Capillary Rise from Surface Tension Estimate liquid rise in a circular capillary using Jurin's law, h = 2γ cosθ/(ρgr). A contact angle above 90° gives a negative height (depression). Assumes a narrow tube and ignores meniscus-shape corrections.
- Catalyst Effect Check Calculate catalyst effect check.
- Cell Potential Calculator Compute the cell potential as the cathode reduction potential minus the anode reduction potential.
- Cell Potential From Gibbs Calculator Convert Gibbs free energy change to cell potential via E° = −ΔG/(nF).
- Charge Balance Checker Sum signed ionic charges and check electroneutrality of a species or solution.
- Charge From Moles Electrons Compute the total charge as moles of electrons times the Faraday constant.
- Charles's Law Calculator Compute the final volume of a gas at constant pressure as initial volume times final temperature over initial temperature in Kelvin.
- Chemical Shift ppm Compute the chemical shift in ppm from a sample frequency relative to a reference frequency at a given spectrometer frequency.
- Chromatographic Resolution Compute chromatographic resolution Rs as twice the retention time separation divided by the summed baseline peak widths.
- Clapeyron Slope Calculator Compute Clapeyron slope dP/dT = dH/(T*dV).
- Clausius Vapor Pressure At T Compute the vapor pressure at a second temperature from the Clausius-Clapeyron relation using a reference pressure and enthalpy of vaporization.
- Clausius–Clapeyron Vapor Pressure Estimate vapor pressure at a second absolute temperature from a reference pressure and molar enthalpy of vaporization using the integrated Clausius–Clapeyron equation. Assumes vapor behaves ideally and enthalpy stays constant over the temperature interval.
- COD Calculator Calculate chemical oxygen demand from blank and sample titrant volumes, titrant normality, and digested sample volume.
- Collision Frequency Calculator Compute collision frequency z = sqrt(2)*pi*d^2*v_bar*n.
- Combined Gas Law Calculator Compute final pressure as initial pressure times initial volume over final volume times final temperature over initial temperature in Kelvin.
- Combustion Carbon Mass Calculator Compute the carbon contained in a burned sample from the CO₂ collected during combustion analysis.
- Combustion Hydrogen Mass Calculator Compute the hydrogen contained in a burned sample from the H₂O collected during combustion analysis.
- Combustion Oxygen Mass Calculator Compute oxygen in the original sample as the remainder after subtracting carbon and hydrogen masses.
- Common Ion Effect Factor Calculator Compute solubility reduction factor from common ion concentration.
- Common Ion Solubility Approximate molar solubility of an AB salt with a large excess of a common ion.
- Compressibility Factor Calculator Compute Z = PV/(nRT) to quantify deviation of a real gas from ideal behavior.
- Conditional Kf Prime Compute the conditional formation constant Kf prime as the product of beta and the ligand alpha fraction.
- Conductivity From Concentration Calculator Compute conductivity kappa = molarConductivity * concentration / 1000.
- Conjugate Acid Ka Compute the Ka of a conjugate acid from the Kb of its conjugate base as Kw divided by Kb.
- Conjugate Base Kb Compute the Kb of a conjugate base from the Ka of its conjugate acid as Kw divided by Ka.
- Contact Process Conversion Calculator Calculate sulfur dioxide conversion percentage for the Contact process from initial and final amounts.
- Coordination Number Calculator Look up the number of nearest neighbours around an atom for the common cubic and close-packed structures.
- Coupling Constant Hz Compute the scalar coupling constant in Hz either from a validated peak separation or from two distinct peak frequencies.
- CP Minus CV Report the Mayer relation for an ideal gas as the difference between molar heat capacities at constant pressure and constant volume.
- Cp Minus Cv Calculator Return the ideal gas Cp-Cv difference which equals R.
- Critical Pressure Lookup Look up the critical pressure of a common substance by name in kilopascals.
- Critical Temperature Lookup Look up the critical temperature of a common substance by name in kelvin.
- Critical Volume Lookup Look up critical volume of a common substance by name.
- Crystal Field Stabilization Energy Calculator Compute the octahedral crystal field stabilization energy in units of the ligand field splitting Delta-o from the t2g and eg electron counts: CFSE = (-0.4*n(t2g) + 0.6*n(eg)) * Delta-o.
- Cubic Interplanar Spacing Calculate dₕₖₗ=a/√(h²+k²+l²) for a cubic crystal. Miller indices cannot all be zero; lattice parameter and output share the same length unit.
- Cubic Lattice Parameter from Density Calculate the cubic unit-cell edge from Z formula units per cell, molar mass, and density: a³=ZM/(ρNₐ). Enter SI molar mass (kg/mol) and density (kg/m³); output is metres.
- Current Efficiency Calculator Compute current efficiency percentage.
- CV For Diatomic Ideal Gas Report the molar heat capacity at constant volume for a diatomic ideal gas as five halves of the gas constant.
- D-Spacing from Bragg's Law Calculator Solve Bragg's law n*lambda = 2*d*sin(theta) for the interplanar spacing d in angstroms.
- Dalton Partial Pressure Compute the partial pressure of a gas as total pressure times its mole fraction.
- Dalton Total Pressure Calculator Sum all partial pressures in a mixture according to Dalton's law of partial pressures.
- De Broglie Wavelength Calculator Calculate the nonrelativistic de Broglie wavelength from particle mass and speed.
- Debye-Huckel Limiting Law Compute an ion activity coefficient in water at 25 °C with the Debye-Hückel limiting law, intended for ionic strength up to 0.01 mol/L.
- Decay Half-Life Calculator Solve the half-life from an initial amount, a remaining amount, and the elapsed time as t½ = t·ln2 / ln(N₀/N).
- Decay Remaining Calculator Compute the remaining amount after radioactive decay as N = N₀·(1/2)^(t/t½).
- Degree of Dissociation Calculator Solve the degree of dissociation from an observed van't Hoff factor as α = (i−1)/(n−1).
- Delta G From K Compute Gibbs free energy change in kJ per mole from the equilibrium constant as -R times T times ln(K).
- Density From Unit Cell Calculator Calculate crystal density from formula-unit molar mass, formula units per cell, and unit-cell volume.
- Dewpoint From Vapor Pressure Invert the Magnus formula to compute dewpoint temperature from water vapor pressure.
- Diffusion Coefficient Calculator Compute the diffusion coefficient from mean squared displacement via D = ⟨x²⟩/(2·d·t).
- Dilution M1V1=M2V2 Calculator Solve V2 from the dilution relation M1V1=M2V2 given stock and target concentrations.
- Dilution pH Strong Acid Calculator Compute the new pH after diluting a strong acid by any factor via C₂ = C₁·(V₁/V₂) then pH = −log(C₂).
- DLVO Interaction Energy Estimate Combine a user-specified exponentially screened electrostatic repulsion with the non-retarded sphere–plate van der Waals term −AR/(6h). This is a simplified DLVO energy model, not a stability verdict for arbitrary colloids.
- Doubly Charged m/z Compute the mass-to-charge ratio of a doubly charged ion as the neutral mass plus two proton masses divided by two.
- EDTA Alpha Y4 Fraction Compute the fraction of uncomplexed EDTA present as fully deprotonated Y4-minus from pH and all four acid dissociation constants.
- Electrochemical Equivalent Calculator Compute electrochemical equivalent Z = M/(n*F) g/C.
- Electrolysis Gas Volume STP Compute the gas volume at STP as moles of gas times 22.414 liters per mole.
- Electrolysis Time Calculator Compute the electrolysis time as moles of metal times electron count times the Faraday constant divided by the current.
- Electron Affinity Lookup Look up electron affinity for an element in kJ/mol.
- Electron Balance Check Check whether total electrons lost in oxidation equal total electrons gained in reduction and report the signed difference.
- Electron Configuration Generator Generate the ground-state electron configuration of a neutral atom using the Aufbau principle.
- Electronegativity Lookup Look up Pauling electronegativity value for an element symbol.
- Electroplating Thickness Calculator Compute deposited metal layer thickness from Faraday's law of electrolysis and convert to micrometers.
- Empirical Formula From CO2 and H2O Calculator Derive the empirical formula CₓHᵧ from combustion analysis CO₂ and H₂O masses normalized to whole-number ratios.
- Empirical Formula From Combustion Calculator Derive C:H mole ratios from combustion CO₂ and H₂O masses, normalized to the smallest amount.
- Empirical Formula From Moles Calculator Compute empirical formula element ratios by dividing each element's mole amount by the smallest mole amount.
- Empirical Ratio Calculator Divide two element mole amounts by the smaller one to obtain whole-number-friendly empirical ratios.
- Enthalpy From Formation Calculator Compute the reaction enthalpy as ΣΔHf(products) − ΣΔHf(reactants) with unit stoichiometric coefficients.
- Enthalpy of Combustion Calculator Compute combustion enthalpy from sum of product minus reactant formation enthalpies.
- Entropy Change Calculator Compute the reaction entropy change as ΣS°(products) − ΣS°(reactants) with unit stoichiometric coefficients.
- Entropy Contribution Scale a standard molar entropy to a total entropy contribution for a given amount in moles.
- Entropy of Fusion Calculator Compute dS_fus = dH_fus / T_m.
- Entropy of Vaporization Calculator Compute dS_vap = dH_vap / T_b.
- Equilibrium Qp Calculator Compute the reaction quotient in terms of partial pressures as Qp = P_B^b / P_A^a for aA ⇌ bB.
- Equilibrium Shift Checker Compare the reaction quotient Q against the equilibrium constant K to determine the direction of shift.
- Equilibrium Temperature Calculator Find crossover temperature where dG = 0: T = dH/dS.
- Equivalent Concentration Calculator Compute the equivalent concentration of a solution as equivalents divided by liters of solution.
- Equivalent Moles Calculator Compute equivalents of a substance as moles times its valence (protons, hydroxides, or electrons transferred).
- Equivalent Weight Calculator Compute the equivalent weight as molar mass divided by valence.
- Excess Enthalpy Compute the excess enthalpy of a mixture as the actual mixing enthalpy minus the ideal mixing enthalpy.
- Excess Reagent Mass Remaining Calculator Convert the leftover moles of an excess reagent into mass using its molar mass.
- Excess Reagent Moles Remaining Calculator Compute the moles of excess reagent left over after the limiting reagent is fully consumed.
- Extraction Efficiency Calculator Compute single extraction efficiency percent from partition coefficient and volume ratio.
- Faraday Mass Deposited Compute the mass deposited in electrolysis as charge times molar mass divided by electron count times the Faraday constant.
- Faraday Moles of Electrons Calculator Convert total electric charge into moles of electrons using Faraday's constant (96485 C/mol).
- First Order Half-Life Compute the half-life of a first order reaction as the natural logarithm of two divided by the rate constant.
- First Order Integrated Rate Calculator Solve the first-order integrated rate law ln([A]₀/[A]) = k·t for the remaining concentration.
- Fluorescence Intensity Compute fluorescence intensity as quantum yield times molar absorptivity times concentration times excitation intensity.
- Fluorescence QY Compare Estimate the sample fluorescence quantum yield relative to a reference standard.
- Formal Charge Calculator Compute the formal charge as valence electrons minus nonbonding electrons minus half of the bonding electrons.
- Formality Calculator Compute formality as formula units dissolved per liter of solution, used for ionic compounds.
- Formation Constant Beta Compute the overall formation constant beta for a metal complex from equilibrium concentrations.
- Formation Enthalpy Sum Scale a standard molar enthalpy of formation to a total enthalpy for a given amount in moles.
- Freezing Point Depression Estimate freezing point depression from molality, the cryoscopic constant, and the van 't Hoff factor.
- Freundlich Adsorption Capacity Calculate equilibrium adsorption capacity q=K C^(1/n) using the empirical Freundlich isotherm. The coefficient K carries units determined by the concentration and capacity units; this model has no saturation limit.
- Fugacity Calculator Compute fugacity f = phi * P.
- Fugacity Coefficient Calculator Compute fugacity coefficient phi = f/P.
- Fugacity From Z Estimate gas fugacity from a pressure-virial compressibility factor using ln(phi) ≈ Z-1 and f = phi·P; this second-virial approximation is for low pressure.
- Gamma Cp/Cv Calculator Compute heat capacity ratio gamma = Cp/Cv.
- Gamma Heat Capacity Ratio Compute the adiabatic index gamma as the ratio of molar heat capacity at constant pressure to that at constant volume.
- Gas Density STP Compute gas density at STP in g/L as molar mass divided by the molar volume of 22.414 liters per mole.
- Gas Solubility at Altitude Calculator Scale sea-level gas solubility by the reduced pressure at altitude via Henry's law proportionality.
- Gay-Lussac Law Calculator Compute the final pressure of a gas at constant volume as initial pressure times final temperature over initial temperature in Kelvin.
- Gibbs Free Energy From Cell Potential Calculator Convert cell potential to Gibbs free energy via ΔG = −nFE with F = 96485 C/mol.
- Gibbs Reaction Calculator Compute standard Gibbs free energy of reaction from products minus reactants.
- Gibbs Surface Excess Estimate surface excess Γ from the slope dγ/dln(activity) using Γ=−slope/(nRT). Supply the appropriate ionic/species factor n; the ideal-activity approximation and chosen slope determine the result.
- Gibbs-Helmholtz Calculator Compute the Gibbs free energy change as ΔG = ΔH − T·ΔS.
- Graham Effusion Rate Compute the effusion rate of a gas as the reference rate times the square root of the reference molar mass over the target molar mass.
- Graham Time of Effusion Calculator Compare effusion times of two gases via Graham's law t₂/t₁ = √(M₂/M₁).
- Gravimetric Factor Compute the gravimetric factor converting precipitate mass to analyte mass via molar mass ratio and stoichiometry.
- Haber-Bosch Equilibrium Calculator Calculate the concentration equilibrium constant for N2 + 3 H2 ⇌ 2 NH3.
- Half-Wave Potential Determine the reversible polarographic half-wave potential at 25 °C from a measured wave point using E₁/₂ = E - (0.0592/n)·log10((i_d-i)/i).
- Hardness as CaCO3 Calculator Calculate water hardness as calcium carbonate equivalent from calcium and magnesium concentrations.
- Heat of Neutralization Calculator Compute heat of neutralization per mole water formed.
- Heat of Solution Calculator Compute solution enthalpy as lattice dissociation enthalpy plus hydration enthalpy, using positive energy to separate the lattice and signed hydration enthalpy.
- Heat Q MCAT Calculator Calculate heat q mcat calculator.
- Heisenberg Uncertainty Calculator Calculate the minimum momentum uncertainty allowed by Heisenberg's uncertainty relation for a given position uncertainty.
- Henderson-Hasselbalch pH Estimate buffer pH from pKa and the ratio of conjugate base to acid concentrations.
- Henry Constant From Solubility Calculator Derive Henry's law constant H = P / C from the partial pressure and dissolved gas concentration at equilibrium.
- Henry's Law Calculator Compute dissolved gas concentration from Henry's law constant and partial pressure.
- Hess Law Calculator Calculate hess law calculator.
- Hess Law Enthalpy Compute the overall reaction enthalpy from Hess law as the summed product enthalpies minus the summed reactant enthalpies.
- Hill Coefficient Calculator Compute the Hill coefficient as the slope between two points on a Hill plot of log10(Y/(1-Y)) versus log10 ligand concentration.
- Hybridization Lookup Look up the orbital hybridization of a central atom from its steric number (bonded atoms plus lone pairs).
- Hydration Enthalpy Sum Scale a molar ion hydration enthalpy to a total enthalpy for a given amount in moles.
- IC50 to Ki Converter Convert IC50 to Ki using Cheng-Prusoff equation Ki = IC50/(1+[S]/Km).
- Ideal Gas Density Compute ideal gas density in g/L as molar mass times pressure over R times temperature using the gas constant in L-atm.
- Ideal Gas Pressure Compute the pressure of an ideal gas as moles times R times temperature over volume.
- Indicator pKa Lookup Look up approximate pKa of common indicators.
- Inhibition Constant Ki Calculator Compute Ki from IC50 via Cheng-Prusoff Ki = IC50/(1+S/Km).
- Inhibitor Effect Check Calculate inhibitor effect check.
- Initial Rate Calculator Calculate initial rate calculator.
- Integration Ratio Normalize two NMR integrals so the smaller value becomes one and report the proton ratios rounded to two decimals.
- Ionic Mobility Calculator Compute ionic mobility mu = lambda/(z*F).
- Ionic Radius Lookup Look up a Shannon effective ionic radius for a common six-coordinate ion; ionic radius depends on oxidation state and coordination number.
- Ionic Strength Activity Calculator Compute ionic strength I = 0.5 * sum(ci * zi^2) for two ion species.
- Ionic Strength Calculator Compute ionic strength from the concentrations and charges of two ions.
- Ionization Energy Lookup Look up first ionization energy for an element in kJ/mol.
- Ionization Energy Rydberg Calculator Calculate the hydrogen-like ionization energy from a principal quantum level using the Rydberg relation.
- ISE Potential Compute the ion selective electrode potential from an intercept and slope applied to the log of the ion concentration.
- Isoelectric Point Calculator Compute the isoelectric point as the average of the two relevant pKa values.
- Isotope Average Mass Calculator Compute the weighted-average atomic mass from isotope masses and their percent abundances.
- Isotope Pattern Ratio Estimate the M+1 to M peak intensity ratio from carbon count times 0.011 for natural 13C abundance of 1.1 percent.
- Isotopic Abundance Calculator Solve the two-isotope percent abundances that produce a known weighted-average atomic mass.
- Joule-Thomson Inversion Calculator Estimate Joule-Thomson inversion temperature Ti = 2a/(Rb).
- Ka From Kb Compute the acid dissociation constant from the base dissociation constant as Kw divided by Kb.
- Ka From pKa Convert a pKa value to the acid dissociation constant Ka.
- Kb From Ka Compute the base dissociation constant from the acid dissociation constant as Kw divided by Ka.
- Kb From pKb Convert a pKb value to the base dissociation constant Kb.
- Kc From Concentrations Calculator Compute the concentration-based equilibrium constant Kc = [B]^b / [A]^a for a reversible reaction aA ⇌ bB.
- Kc From Equilibrium Conc Compute the equilibrium constant Kc as equilibrium product concentration to power p over reactant concentration to power r.
- Kinetic Energy Gas Calculator Compute average kinetic energy per molecule KE = 3/2*kT.
- Kirchhoff Law Calculator Compute dH(T2) = dH(T1) + dCp*(T2-T1).
- Kohlrausch Law Calculator Compute limiting molar conductivity from ionic contributions.
- Kp From Kc Calculator Relate gas-phase equilibrium constants via Kp = Kc·(RT)^Δn where Δn is products minus reactants coefficients.
- Kp From Partial Pressures Calculator Compute the pressure-based equilibrium constant Kp = P_B^b / P_A^a for a reversible reaction aA ⇌ bB.
- Langmuir Surface Coverage Compute fractional site occupancy θ=KC/(1+KC) for a single-site Langmuir adsorption model. Concentration and K must use reciprocal units. This assumes equivalent sites, monolayer adsorption, and no adsorbate interactions.
- Lattice Energy Madelung Estimate electrostatic Madelung energy U = -138.935*A*|z+z-|/r for an ion pair, with interionic distance r in nanometres; short-range repulsion is not included.
- Lewis Structure Notation Generator Format a Lewis structure notation string from element symbol and valence electron count.
- Limiting Reagent Excess Amount Calculator Compute the leftover moles of an excess reagent after complete consumption of the limiting reagent.
- Limiting Reagent Finder Identify the limiting reagent and the product amount for a reaction needing ratioAB moles of B per mole of A.
- Lineweaver-Burk Slope Calculator Compute Lineweaver-Burk slope Km/Vmax.
- Log K From Cell Potential Compute the base-10 logarithm of the equilibrium constant as electron count times standard cell potential divided by 0.0592.
- Madelung Constant Lookup Look up the electrostatic Madelung constant for common ionic crystal structures.
- Mass Defect Calculator Compute the nuclear mass defect Δm = Z·m(H) + N·m(n) − measured atomic mass.
- Mass Fraction to Mole Fraction Converter Convert component mass fractions to mole fractions for a binary mixture via x₁ = (w₁/M₁)/(w₁/M₁ + w₂/M₂).
- Mass Fraction to PPM Converter Convert a mass fraction between zero and one into parts per million by multiplying by one million.
- Mass Percent Calculator Compute the mass percent of a component within a total solution mass.
- Mass Spec m/z Calculator Compute the mass-to-charge ratio as the neutral mass plus charge times the proton mass divided by the charge.
- Mean Free Path Calculator Compute mean free path lambda = kT/(sqrt(2)*pi*d^2*P).
- Mean Ionic Activity Compute the mean ionic activity coefficient for a 1:1 electrolyte as the square root of the cation and anion coefficient product.
- Michaelis-Menten Rate Calculator Compute Michaelis-Menten rate v = Vmax*S/(Km+S).
- Mixing Enthalpy Compute ΔH_mix as the measured mixture molar enthalpy minus the mole-fraction-weighted pure-component enthalpies; an ideal solution gives zero.
- Mixing Ratio Calculator Compute the water vapor mass mixing ratio in grams per kilogram of dry air.
- Molality Calculator Compute molality from solute moles and solvent mass.
- Molality From Molarity and Density Calculator Convert molarity to molality using solution density and solute molar mass via m = M/(ρ − M·Mw/1000).
- Molar Absorptivity Calculator Compute molar absorptivity from measured absorbance, concentration, and path length.
- Molar Absorptivity From Slope Calculator Derive molar absorptivity ε from a Beer-Lambert calibration slope (A = ε·b·c) and the path length.
- Molar Conductivity Calculator Compute molar conductivity lambda = kappa * 1000 / c.
- Molar Cp Input Validation Validate a molar heat capacity Cp in J/(mol·K) within the physical range (0, 500] and pass it through.
- Molar Cv From Cp Compute the molar heat capacity at constant volume from Cp using the ideal gas relation Cv = Cp − R.
- Molar Mass From Effusion Calculator Apply Graham's law to find molar mass from effusion rates M2 = M1*(r1/r2)^2.
- Molar Mass From Formula Weight Convert a formula weight into an equivalent molar mass in grams per mole.
- Molar Mass From Vapor Density Air Calculator Estimate molar mass from vapor density relative to air using M = 28.96 × VD(air).
- Molar Mass From Vapor Density H2 Calculator Estimate molar mass from vapor density relative to hydrogen gas using M = 2.016 × VD(H₂).
- Molar Volume STP Check Compute the ideal molar volume at STP in milliliters per mole and the percent deviation of a measured molar volume from it.
- Molarity Calculator Compute solution molarity from solute moles and volume.
- Molarity From Molality and Density Calculator Convert molality to molarity using solution density and solute molar mass via M = mρ/(1 + m·Mw/1000).
- Mole Fraction Calculator Compute the mole fraction of component A in a binary mixture with component B.
- Mole Fraction to Mass Fraction Converter Convert component mole fractions to mass fractions for a binary mixture via w₁ = x₁M₁/(x₁M₁ + x₂M₂).
- Molecular Multiplier Calculator Determine how many empirical formula units make up the molecular formula.
- Molecular Weight From Vapor Density Calculator Compute molar mass from vapor density via the ideal gas relation M = dRT/P.
- Moles Electrons From Charge Compute the moles of electrons as charge divided by the Faraday constant.
- Moles From Mass Compute the amount of substance from mass and molar mass.
- Most Probable Speed Compute the most probable molecular speed of a gas from temperature and molar mass.
- Multiple Extraction Calculator Compute fraction remaining after n extractions.
- Nernst Equation Calculator Compute cell potential as the standard potential minus 0.0592 over electron count times log10 of the reaction quotient.
- Nernst Slope Check Compare a measured electrode slope against the ideal Nernst slope of 59.16 mV per charge at 25 degrees Celsius.
- Neutron Separation Energy Calculator Calculate one-neutron separation energy from parent and daughter nuclear masses.
- Normality Calculator Compute solution normality as equivalents per liter from moles, equivalents per mole, and volume.
- Normality From Molarity Calculator Compute normality as molarity times equivalents per mole (N = M × n).
- Nuclear Packing Fraction Calculator Calculate the conventional nuclear packing fraction from isotopic atomic mass and mass number, reported in parts per ten thousand.
- Nuclear Q-Value Calculator Calculate a nuclear reaction Q value from the initial and final masses using mass-energy equivalence.
- Number-Average Degree of Polymerization Estimate number-average polymerization degree as number-average molecular mass divided by repeat-unit molar mass. Both masses must use the same unit; end-group mass is neglected.
- Octahedral Jahn-Teller Distortion Checker Check whether an octahedral complex has uneven e_g occupancy and therefore a strong Jahn-Teller distortion; t2g-only weak distortions are outside this check.
- Osmolality Calculator Compute solution osmolality as the van't Hoff factor times molality.
- Osmolarity Calculator Compute solution osmolarity as the van't Hoff factor times molarity.
- Osmotic Coefficient Calculator Compute osmotic coefficient phi = osmolality/(i*m).
- Osmotic Pressure Calculator Compute osmotic pressure from molarity, temperature, and the van 't Hoff factor.
- Overpotential Calculator Compute signed electrode overpotential eta = E_applied - E_equilibrium on the same reference-electrode scale.
- Oxidation Number Calculator Solve the average oxidation state of one element in an ion or compound from a known element's state and the total charge.
- Packing Efficiency Calculator Compute the percent of a unit cell volume filled by hard-sphere atoms for the common cubic and close-packed packings.
- Packing Fraction Calculator Calculate the hard-sphere packing fraction of a unit cell from atomic radius, atom count, and unit-cell volume.
- Particle Count Calculator Compute the number of particles from an amount of substance using Avogadro's constant.
- Particle in a Box Energy Calculator Calculate the energy of a quantum level for a particle in a one-dimensional infinite potential well.
- Partition Coefficient Calculator Compute partition coefficient Kd = C_organic/C_aqueous.
- Path Length From Beer Law Compute the optical path length from the Beer-Lambert law as absorbance divided by molar absorptivity times concentration.
- Peak Asymmetry Factor Compute the peak asymmetry factor as the tail half width divided by the front half width measured at ten percent peak height.
- Percent Analyte Gravimetry Compute the mass percent of analyte in a sample from precipitate mass and gravimetric factor.
- Percent Carbon From Combustion Calculator Express the carbon recovered from combustion CO₂ as a percentage of the original sample mass.
- Percent Composition Calculator Compute the mass percentage an element contributes to a compound's molar mass.
- Percent Dissociation Weak Acid Calculator Compute monoprotic weak-acid percent dissociation by solving Ka = x²/(C-x), without assuming x is negligible relative to C.
- Percent Ionization Calculator Compute the percent ionization of a weak acid as ([H⁺]dissociated / [HA]initial) × 100.
- Percent Yield Calculator Compare an actual product mass against the theoretical yield as a percentage.
- pH From H Plus Compute pH as the negative base-10 logarithm of the hydrogen ion concentration.
- pH From pOH Compute pH as fourteen minus pOH.
- pH Ionic Strength Corrected Calculator Correct measured pH by adding an ionic strength adjustment term.
- pH Strong Acid Dilution Calculator Compute pH after diluting a strong acid by any factor.
- pH With Activity Compute pH from the hydrogen ion activity as the negative log10 of the activity coefficient times the hydrogen ion concentration.
- Phenolphthalein Range Checker Check whether a pH falls within phenolphthalein transition range 8.2-10.0.
- Plate Height H Compute the plate height H in micrometers as the column length converted to micrometers divided by the plate number.
- Plate Number N Compute the theoretical plate number N as sixteen times the square of the ratio of retention time to baseline peak width.
- pM At Equivalence Compute pM at the equivalence point of a 1:1 sparingly soluble salt as minus log base ten of the square root of Ksp.
- pOH From OH Minus Compute pOH as the negative base-10 logarithm of the hydroxide ion concentration.
- Polymer Dispersity Calculate polymer dispersity Đ=Mw/Mn from weight-average and number-average molar masses. For a valid nonnegative molecular-weight distribution, Mw should not be below Mn.
- Polymer Number-Average Molecular Mass Calculate Mn=ΣNiMi/ΣNi from counts of polymer chains in each molar-mass bin. Counts and masses must have equal, nonempty lengths; masses should use a consistent unit.
- Polymer Weight-Average Molecular Mass Calculate Mw=ΣNiMi²/ΣNiMi from a polymer chain-count distribution. Heavy chains contribute disproportionately, so Mw is normally at least Mn for the same distribution.
- Polyprotic pH First Step Compute the pH of a polyprotic acid solution from its first dissociation step as the negative log10 of the square root of ka1 times concentration.
- PPB Calculator Compute concentration in parts per billion from micrograms of solute per kilogram of solution.
- PPB to Molarity Converter Convert parts-per-billion (µg/L) aqueous concentration to molarity via M = ppb/(10⁶·Mw).
- PPB to PPM Converter Convert parts per billion into parts per million by dividing by one thousand.
- PPM Calculator Compute concentration in parts per million from milligrams of solute per kilogram of solution.
- PPM to Mass Percent Converter Convert parts-per-million into mass percent by dividing by ten thousand.
- PPM to Molarity Converter Convert parts-per-million (mg/L) aqueous concentration to molarity via M = ppm/(1000·Mw).
- Precipitate Mass From Analyte Compute the precipitate mass needed for a given analyte mass using the gravimetric factor.
- Precipitation Checker Determine whether a precipitate forms by comparing the ion product Q to the solubility product Ksp.
- Pseudo First Order Rate Compute the observed pseudo first order rate constant for a second order reaction with one reactant in large excess.
- Qc vs Kc Checker Compare the concentration-based quotient Qc against Kc to determine whether products or reactants are favored going forward.
- Quantum Yield Calculator Compute fluorescence quantum yield as the number of photons emitted divided by the number of photons absorbed.
- Rate Determining Step Checker Compare two directly comparable elementary-step rate constants; the smaller constant identifies the slower step, while equal constants have no unique slower step.
- Rate Law Calculator Compute the reaction rate from the rate constant and reactant concentrations raised to their reaction orders.
- Reaction Extent Calculator Compute the extent of reaction ξ = (initial − remaining) / stoichiometric coefficient for a reactant.
- Reaction Quotient Q Calculator Compute the reaction quotient as product concentration to power p over reactant concentration to power r.
- Reaction Yield Mass Calculator Compute the actual product mass from product moles, molar mass, and a percent yield.
- Real Gas Correction A Calculator Compute van der Waals pressure correction term a(n/V)^2.
- Real Gas Correction B Calculator Compute excluded volume n*b from van der Waals constant b.
- Redox Equivalent Weight Compute the redox equivalent weight as molar mass divided by the number of electrons transferred per formula unit.
- Redox Normality Compute redox normality as molarity times the number of electrons transferred per formula unit.
- Reduced Pressure Calculator Compute dimensionless Pr = P/Pc.
- Reduced Temperature Calculator Compute dimensionless Tr = T/Tc.
- Reduced Volume Calculator Compute reduced volume Vr = V/Vc.
- Relative Humidity Calculator Compute relative humidity as the ratio of actual to saturation vapor pressure.
- Resonance Count Tool Count the number of specified resonance structures.
- Retention Factor k Compute the chromatographic retention factor k as adjusted retention time divided by the column dead time.
- RMS Speed Calculator Compute the root-mean-square speed of gas molecules from temperature and molar mass.
- Rydberg Wavelength Calculator Calculate the wavelength of a hydrogen-like electronic transition using the Rydberg formula.
- Scale Height Calculator Compute the atmospheric scale height over which pressure falls by a factor of e.
- Scherrer Equation Calculator Estimate crystallite domain size with the Scherrer equation D = K*lambda/(beta*cos(theta)) from XRD peak broadening.
- Second Order Half-Life Calculator Compute the second-order half-life t½ = 1/(k·[A]₀) from a rate constant and initial concentration.
- Second Order Integrated Rate Calculator Solve the second-order integrated rate law 1/[A] = 1/[A]₀ + k·t for the remaining concentration.
- Selectivity Alpha Compute chromatographic selectivity alpha as the retention factor of peak B divided by the retention factor of peak A.
- Serial Dilution Calculator Compute the final concentration after a series of identical dilution transfers.
- Serial Dilution Factor Calculator Compute the total cumulative dilution factor across a serial dilution as (dilution per step)^steps.
- Shift Relative To Reference Compute the NMR chemical shift in ppm of a sample frequency relative to a reference frequency.
- Signal To Noise Ratio Compute the analytical signal to noise ratio from the mean signal and the noise standard deviation.
- Solubility From Ksp Compute molar solubility from the solubility product for AB or AB2 salts.
- Solubility MX2 Calculator Compute molar solubility s of an MX2 salt from Ksp = 4s^3.
- Solubility MX3 Calculator Compute molar solubility s of an MX3 salt from Ksp = 27s^4.
- Solubility Product Quotient Calculator Compute the reaction quotient Q = [A]ˣ[B]ʸ for a dissolving salt and compare it against Ksp.
- Solubility vs pH Ratio Compute the solubility enhancement ratio in acidic solution as one plus hydrogen ion concentration over Ka.
- Solubility With Ionic Strength Calculator Estimate molar solubility of a symmetric 1:1 electrolyte at 25 °C using s = s₀·10^(0.509·z²·√I), within the Debye-Hückel limiting-law range.
- Solute Mass For Molarity Compute the solute mass needed to reach a target molarity in a given volume.
- Solution Density From Molarity Calculator Derive solution density from molarity and molality via rearranged interconversion ρ = M(1 + mMw/1000)/m.
- Specific Activity Calculator Compute the specific activity of a radioactive sample as activity divided by sample mass.
- Specific Heat Calculator Calculate specific heat calculator.
- Specific Humidity Calculator Compute the specific humidity in grams of water vapor per kilogram of moist air.
- Spectrochemical Series Lookup Find a ligand's position in an abbreviated spectrochemical series ordered from weak-field to strong-field ligands.
- Spin-Only Magnetic Moment Calculator Compute the spin-only magnetic moment mu = sqrt(n*(n+2)) in Bohr magnetons for n unpaired electrons.
- Spontaneity Checker Classify reaction spontaneity from sign of dG.
- Standard Cell Potential Compute E°cell = E°cathode(reduction) - E°anode(reduction) from tabulated standard reduction potentials.
- Standard Hydrogen Electrode Correction Calculator Correct electrode potential via Nernst E = E0 - (0.0592/n)*log(Q).
- Standard State Correction Calculator Compute RT*ln(Q) correction term for non-standard conditions.
- Standardization Factor Calculator Calculate an analytical standardization factor as actual concentration divided by nominal concentration.
- Stern-Volmer Ratio Compute the Stern-Volmer ratio F0/F as one plus the Stern-Volmer constant times the quencher concentration.
- Strong Acid pH Compute the pH of a strong acid solution from its concentration.
- Strong Base pH Compute the pH of a strong base solution from its concentration.
- Theoretical Yield Calculator Compute the maximum product mass from the limiting reagent amount and product molar mass.
- Titration Blank Correction Calculator Correct a titration sample volume by subtracting the titrant volume consumed by a blank.
- Titration Curve Slope Calculator Compute dpH/dV slope at given point during titration.
- Titration Equivalence Moles Calculator Compute the titrant moles required at the equivalence point from the analyte moles and proton/hydroxide stoichiometry.
- Titration Equivalence Volume Calculator Compute equivalence volume V_eq = n_analyte/C_titrant for a 1:1 stoichiometric titration.
- Titration Indicator Selection Tool Select an appropriate acid-base indicator whose transition range brackets the equivalence point pH.
- Titration pH After Equivalence Calculator Compute the pH after the equivalence point in a strong acid / strong base titration from excess hydroxide.
- Titration pH Before Equivalence Calculator Compute the pH of a weak acid / strong base titration before the equivalence point using Henderson-Hasselbalch.
- Titration pH Strong Acid Base Calculator Compute the pH after mixing strong acid and strong base moles from the excess hydronium or hydroxide in the total volume.
- TOC Calculator Calculate total organic carbon by subtracting inorganic carbon from total carbon.
- Total Nuclear Binding Energy Calculator Calculate total nuclear binding energy from a nucleus mass defect using E = mc².
- Transport Number Calculator Compute cation transport number fraction.
- Triprotic Amphiprotic Species pH Estimate Estimate the pH of either intermediate amphiprotic form of a triprotic acid from the average of its adjacent pKa values.
- Trouton Rule Calculator Estimate enthalpy of vaporization via Trouton rule dHvap = 85*Tb J/mol.
- Trouton Rule Estimate Estimate the enthalpy of vaporization from the boiling point using Trouton's rule with a 85 J/(mol·K) entropy of vaporization.
- Turnover Frequency Compute the catalyst turnover frequency as moles of product formed per second per mole of catalyst.
- Turnover Number Calculator Compute catalytic turnover number as TON = moles product / moles catalyst.
- Unit Cell Density Calculator Compute the theoretical crystal density rho = Z*M/(N_A*a^3) from the atoms per unit cell, molar mass, and cubic edge length.
- Unit Cell Volume Calculator Compute the orthogonal unit cell volume as the product of the three lattice edges; equal edges give the cubic cell volume.
- USP Tailing Factor Compute the USP tailing factor as the total peak width at five percent height divided by twice the front half width.
- Van der Waals Pressure Correction Calculator Compute the corrected pressure from the van der Waals equation P = nRT/(V−nb) − a(n/V)².
- Van der Waals Volume Correction Calculator Compute the excluded volume n·b subtracted from container size in the van der Waals equation.
- Van't Hoff Equation Calculator Solve for K2 using ln(K2/K1) = -dH/R(1/T2-1/T1).
- Van't Hoff Factor Calculator Compute the effective van't Hoff factor from the degree of dissociation and ions per formula unit as i = 1 + α(n−1).
- Van't Hoff K2 Compute the natural log of an equilibrium constant at a second temperature with the van 't Hoff relation from the reaction enthalpy and a known value at a first temperature.
- Van't Hoff Transition Temperature Compute the Van't Hoff transition temperature as the ratio of enthalpy and entropy changes.
- Vapor Density Relative to Air Calculator Compute vapor density relative to air as the ratio of molar masses M(gas)/28.96.
- Vapor Density Relative to H2 Calculator Compute vapor density relative to hydrogen as the ratio of molar masses M(gas)/M(H₂).
- Vapor Pressure Clausius-Clapeyron Calculator Compute P2 = P1 * exp[-dHvap/R * (1/T2 - 1/T1)].
- Vapor Pressure From Dewpoint Compute water vapor pressure from dewpoint temperature using the Magnus formula.
- Vapor Pressure Lowering Estimate relative vapor pressure lowering from the solute mole fraction.
- Vapor Pressure of Solution Calculator Apply Raoult's law to compute solvent vapor pressure above a solution from its mole fraction.
- Void Fraction Calculator Calculate the unoccupied fraction of a unit cell as one minus its packing fraction.
- Volume For Moles Calculator Compute the solution volume that contains a given amount of solute at a given molarity.
- Volume Percent Calculator Compute the volume percent of a component within a total solution volume.
- VSEPR Geometry Lookup Look up the VSEPR molecular geometry from the number of bonded atoms and lone pairs on a central atom.
- Water Ion Product Calculator Compute the ion product Kw = [H⁺]·[OH⁻] from measured hydronium and hydroxide concentrations.
- Weak Acid pH Compute the ideal pH of a monoprotic weak acid by solving Ka = x²/(C-x), without the small-dissociation approximation.
- Weak Base pH Compute the ideal pH of a weak base by solving Kb = x²/(C-x), then converting pOH to pH at 25 °C.
- Wet Bulb Approximation Approximate wet bulb temperature from air temperature and relative humidity using the Stull formula.
- Young Contact Angle Calculate the equilibrium contact angle from solid–vapor, solid–liquid, and liquid–vapor interfacial energies using Young's equation. Valid only when the resulting cosine lies between −1 and 1; surface roughness and hysteresis are not modeled.
- Z Factor Virial Calculator Compute compressibility Z = PV/(nRT) with second virial correction.
- Zero Order Half-Life Calculator Compute the zero-order half-life t½ = [A]₀/(2k) from a rate constant and initial concentration.
- Zero Order Integrated Rate Calculator Solve the zero-order integrated rate law [A] = [A]₀ − k·t for the remaining concentration, clamped at zero.
- Zeta Potential from Henry Equation Estimate zeta potential from electrophoretic mobility using Henry's equation ζ=3ημ/(2εf). Supply dynamic viscosity, absolute permittivity, and Henry function f(κa); the result depends on the electrokinetic regime.