Solutions & Concentrations

  • A260/A280 Purity Ratio Calculator
    Calculate the A260/A280 absorbance ratio to assess DNA and RNA sample purity. Enter your spectrophotometer readings for an instant nucleic acid quality check.
  • pH to H+ Concentration Calculator
    Convert a pH value to hydrogen ion concentration [H+] using [H+] = 10^(−pH). Also returns pOH and [OH−]. Fast, accurate chemistry tool.
  • Moles of Gas Calculator (PV = nRT)
    Calculate moles of an ideal gas from pressure, volume and temperature using PV = nRT. Enter P in atm, V in liters, T in kelvin to get n in moles.
  • pH Calculator from Concentration
    Calculate pH from hydrogen ion concentration [H+] using pH = -log10([H+]). Also returns pOH and [OH-]. Free, instant chemistry tool.
  • % w/v to mg/mL Calculator
    Convert percent weight/volume (% w/v) concentration to milligrams per milliliter (mg/mL) instantly. Uses mg/mL = %w/v × 10. Free pharmacy & lab tool.
  • Liters to Moles Calculator
    Convert liters of gas to moles using the molar volume. At STP a gas occupies 22.4 L/mol, so n = V / 22.4. Fast, accurate chemistry conversion.
  • pH from pOH Calculator
    Convert pOH to pH instantly with pH = 14 − pOH at 25°C. Also shows [H⁺] and [OH⁻] ion concentrations for any solution.
  • Moles to Liters Calculator (Gas at STP)
    Convert moles of gas to liters at STP using the molar volume (22.4 L/mol). Fast, accurate moles-to-volume calculator for chemistry problems.
  • mg/L to ppm Conversion Calculator
    Convert milligrams per liter (mg/L) to parts per million (ppm) for dilute aqueous solutions. Adjust for solution density. Also shows ppb.
  • pH of Weak Base Calculator
    Calculate the pH, pOH and [OH⁻] of a weak base solution from its Kb and concentration using the square-root approximation [OH⁻] = √(Kb·C).
  • Nernst Equation Calculator
    Calculate cell potential (EMF) with the Nernst equation at 25°C. Enter standard potential E°, electrons transferred n, and reaction quotient Q.
  • RNA Concentration Calculator
    Calculate RNA concentration from A260 absorbance using the 40 ng/µL factor and dilution. Get ng/µL and total RNA yield in µg instantly.
  • pH After Mixing Strong Acid and Base Calculator
    Calculate the pH after mixing a strong acid and strong base. Enter concentrations and volumes to find excess ions, ion concentration, and final pH.
  • Equilibrium Constant (Kc) Calculator
    Calculate the equilibrium constant Kc from product and reactant molar concentrations and their stoichiometric coefficients. Free chemistry tool.
  • Solubility Product (Ksp) Calculator
    Calculate the solubility product Ksp from equilibrium ion concentrations for any salt AaBb. Enter ion molarities and stoichiometric coefficients to get Ksp and pKsp.
  • %w/v to Molarity Calculator
    Convert a percent weight/volume (%w/v) concentration to molarity (mol/L) instantly. Enter the %w/v and molar mass to get the molar concentration.
  • Limiting Reagent Calculator
    Find the limiting reagent of any reaction. Enter the moles and stoichiometric coefficient of each reactant to see which runs out first.
  • Number of Molecules Calculator
    Calculate the number of molecules in a sample from its mass in grams and molar mass using Avogadro number (6.022×10²³). Free chemistry tool.
  • Percent Composition of a Compound Calculator
    Calculate the percent composition by mass of an element in a chemical compound using number of atoms, atomic mass, and molar mass.
  • Reaction Stoichiometry Mass Calculator
    Calculate the mass of product formed from a reactant using molar masses and balanced equation coefficients. Free stoichiometry calculator.
  • Mole Ratio Calculator
    Free stoichiometry mole ratio calculator. Convert moles of substance A to moles of B using balanced equation coefficients. Fast, accurate, and easy.
  • mg/L to Molarity Calculator
    Convert a concentration in mg/L to molarity (mol/L) using the molar mass. Get results in M, mM, and µM instantly with this free calculator.
  • pOH Calculator from [OH⁻]
    Calculate pOH from hydroxide ion concentration using pOH = -log10([OH-]). Instantly find pOH and the corresponding pH at 25°C.
  • Theoretical Yield Calculator
    Calculate the theoretical yield in grams from moles of limiting reactant, reaction coefficients, and molar mass. Optionally find percent yield.

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