Enrichment · Passion Projects · Lab skills

One solution,
every unit.

Type one concentration in the unit you have. The converter gives it in every other common unit and the exact grams to weigh for your flask.

Convert my solutionWhat you get

The solution concentration converter

The worked example is 500 mL of 0.9 percent saline for a biology lab. Nothing you type leaves this browser.

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What you get

Enrichment · Passion ProjectsFree

What you finish with
The concentration in mol/L, mmol/L, g/L, mg/mL, percent w/v and ppm, the grams to weigh and moles for your volume, and masses for common flask sizes. It prints as a prep card for the bench.
Who it is for
Chemistry and biology students, teachers preparing a lab, and hobbyists mixing solutions for gardening, aquariums or photography.
Format
Browser converter for a phone, tablet or computer, by touch or keyboard. Prints a summary; downloads a spreadsheet (.csv); export and import a file.
Access
Free. No account, no sign-in and nothing to install. Everything you type stays in this browser; nothing is sent to Caveat.
Where it lives
The Passion Projects space in Caveat Enrichment.
Support
Questions, a correction or a request: team@caveatacademic.com.

How to use it

  1. Find the molar mass.
  2. Type the concentration you have.
  3. Pick its unit.
  4. Type the volume to make.
  5. Weigh, dissolve, fill to the mark.

Convert my solution

How the units connect

Everything through grams per liter.

The worked example: saline for an onion-cell lab0.9% w/v0.9 gin every 100 mLg/L9× 10mol/L0.154÷ 58.44 g/molFor 500 mL4.5 gof NaClThe worked example: saline for an onion-cell lab0.9% w/v0.9 gin every 100 mLg/L9× 10mol/L0.154÷ 58.44 g/molFor 500 mL4.5 gof NaCl
Every unit passes through grams per liter; the molar mass turns grams into moles; the volume turns a concentration into a mass to weigh.

The units

Molarity counts moles of solute in a liter of solution. Grams per liter and milligrams per milliliter are the same number. Percent weight per volume is grams in 100 milliliters, so 0.9 percent is 9 grams a liter. Parts per million equals milligrams a liter only for dilute water solutions, whose liter weighs about a kilogram.

Making it

Weigh the solute, dissolve it in less water than you need, then add water until the solution reaches the volume mark. Adding the solute to the full volume of water makes the solution slightly too dilute. Solutions for drinking, injecting or medical use are not made this way.

Sources

  1. National Institute of Standards and Technology. NIST Chemistry WebBook: sodium chloride molar mass (webbook.nist.gov).
  2. National Institute of Standards and Technology. Guide for the Use of the International System of Units (SI), Special Publication 811 (nist.gov).
  3. U.S. Environmental Protection Agency. Water quality units: mg/L and ppm (epa.gov).
  4. Occupational Safety and Health Administration. Laboratory safety guidance (osha.gov).

For classroom and hobby use. Follow your lab’s safety rules and the chemical’s safety data sheet. Your entries stay in this browser. Support: team@caveatacademic.com.