How to use (3 steps)
- Choose a mode: from solid reagent, from stock solution (C1V1 = C2V2) or serial dilution series.
- Enter the solute name, molar mass, target concentration and volume, or the stock concentration, factor and tube count.
- Read off the required mass/volumes and numbered recipe steps, then copy the URL to share the setup.
Default examples use NaCl so you can adapt a realistic recipe quickly once you press compute.
Key formulas (for review)
This calculator is built around a small set of concentration formulas. Reviewing them helps you connect what you see on screen with the algebra.
- Molarity: C = n / V
- C is concentration in mol/L, n is amount in mol and V is volume in L. From this you can move between moles, mass (via molar mass M in g/mol) and volume.
- Dilution: C₁V₁ = C₂V₂
- For simple dilutions, the moles before and after are equal. C₁ and V₁ are the stock concentration and volume; C₂ and V₂ are the diluted concentration and final volume.
- Percent solutions (% w/v and % w/w)
- % w/v means grams of solute per 100 mL of solution. % w/w means grams of solute per 100 g of solution (here we approximate aqueous solutions using 1 g/mL for water).
As you read the calculation steps, try to match each line to one of these formulas.
Practice examples
Example 1 — NaCl solution from solid
You need 0.20 M NaCl and 250 mL of solution. Roughly how many grams of NaCl are required? Hint: use C = n/V with C = 0.20 mol/L and V = 0.250 L, then m = n·M with M = 58.44 g/mol. The calculator should give about 2.9 g.
Example 2 — Dilution from a stock solution
You have a 2.0 M HCl stock and want 100 mL of 0.50 M HCl. Use C₁V₁ = C₂V₂ with C₁ = 2.0, C₂ = 0.50 and V₂ = 0.100 L to find V₁. The calculator should suggest pipetting about 25 mL of stock and diluting to 100 mL.
Results
Mode: From solid reagent
These values show what to weigh or pipette; use the calculation steps below to see how the formulas are applied.
Preparation steps
- Weigh out about 0.5844 g of NaCl on an analytical balance.
- Dissolve it in roughly 70 mL of distilled water.
- Transfer to a clean 100 mL volumetric flask, rinse the beaker into the flask, then dilute to the mark and mix.
Serial dilution table
How it's calculated
- Target moles: n = C·V = 0.1 mol/L × 0.1 L = 0.01 mol.
- Mass from molar mass: m = n·M = 0.01 × 58.44 = 0.5844 g.
- Start below the final volume so the dissolved solution can be diluted accurately to 100 mL.
FAQ
What kinds of solution recipes can this tool generate?
The calculator covers three common lab tasks: preparing a solution from a solid reagent at a chosen concentration and volume, diluting a concentrated stock to a target concentration using C₁V₁ = C₂V₂, and building a serial dilution series with a fixed dilution factor and number of tubes.
Does this replace good lab practice or safety checks?
No. The tool provides idealised recipes based on simple concentration formulas and assumes routine aqueous solutions. You should still follow your lab’s safety rules, check units and significant figures, and adapt the volumes or glassware to the available equipment and your protocol.
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