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.

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