Pro Tier Module
Dilution & Molarity Calculator
Five exact bench-chemistry tools - dilution, molarity, serial, percent, and buffer pH - all in-browser.
This tool runs inside GDBS Pro. What it computes and the authorities it applies are below.
The problem
Bench scientists repeatedly solve dilution, molarity, serial-dilution, percent, and buffer-pH problems by hand or in scattered spreadsheets, where a transposed molar mass or pKa silently produces a wrong concentration.
The local-first solution
This plugin computes all five from the stoichiometric and equilibrium definitions with exact arithmetic and base-10 logs entirely in your browser, surfacing the molar mass, density, and pKa it used so a wrong constant cannot hide.
What it does
C1V1 = C2V2 dilution solving for any missing term plus stock and diluent volumes
Molarity from any of mass, molar mass, volume, or concentration (M = mol / L)
Serial dilution with final concentration C0 / f^n and per-step transfer volumes
Percent w/v and v/v to molarity using a sourced density where needed
Henderson-Hasselbalch buffer pH and the [A-]/[HA] ratio for a target pH
Echoes every sourced molar mass, density, and pKa actually used
Honest scope
Every dilution, molarity, serial-dilution power, percent, and Henderson-Hasselbalch computation is exact arithmetic over the stated definitions with no fitting; molar mass, neat-solute density, and pKa are sourced reference inputs you confirm for your exact compound and conditions. Activity-coefficient and ionic-strength corrections, temperature dependence, volume non-additivity, and polyprotic speciation are not modeled. Not a substitute for validated lab procedure or an SDS, and not clinical-dosing advice.
Authorities cited
- C1V1 = C2V2 dilution relation (conservation of moles of solute on dilution): Skoog, West, Holler & Crouch, "Fundamentals of Analytical Chemistry" (solution concentration / dilution); Atkins & de Paula, "Physical Chemistry".
- Amount (molar) concentration c = n/V, n = m/M: IUPAC Green Book ("Quantities, Units and Symbols in Physical Chemistry"); molarity = mass / (molar mass x volume in litres).
- IUPAC 2021 standard atomic weights (used to compute molar masses, e.g. NaCl = 22.990 + 35.45 = 58.44 g/mol): Prohaska et al., Pure Appl. Chem. (IUPAC Commission on Isotopic Abundances and Atomic Weights).
- Serial dilution geometric relation final = C0 / f^n, total dilution f^n: standard microbiology/analytical practice (e.g. Madigan et al., "Brock Biology of Microorganisms", plating/serial dilution).
- Percent concentration identities: %w/v = g per 100 mL (g/L = %w/v x 10); %v/v = mL per 100 mL; molarity from %v/v requires neat-solute density - Skoog et al. (solution concentration chapter).
- Henderson-Hasselbalch equation pH = pKa + log10([A-]/[HA]): L. J. Henderson (1908) and K. A. Hasselbalch (1916); Nelson & Cox, "Lehninger Principles of Biochemistry" (buffers).
- pKa values at 25 C (acetic 4.76; phosphate pKa2 7.20; Tris 8.06; carbonic pKa1 6.35; HEPES 7.55; citric pKa1 3.13) and neat-solute densities (ethanol 0.789, methanol 0.792, glycerol 1.261, glacial acetic 1.049 g/mL): CRC Handbook of Chemistry and Physics (dissociation constants of acids; densities). Confirm for your temperature/ionic strength.
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Run the bench math
Enter your values and get exact concentrations and pH in the browser - nothing is uploaded. Save the run to a Sandbox workspace, attach it to a Worklog case, or share via a Gate client portal.