SolutionPrep

A solution preparation calculator for the browser and WeChat. Convert a known solute mass into a final solution volume, or calculate the mass needed for a chosen final volume and molarity.

Open the web app · Download test packages · WeChat testing guide

Choose how to try it

Version	Start here	What you need
Web app	Open SolutionPrep	A browser; no account or installation
Offline web	Download SolutionPrep-v1.0.0-web.zip from Releases, extract and open index.html	A browser; clipboard availability depends on the browser
WeChat simulator	Download SolutionPrep-v1.0.0-miniprogram.zip, extract and import the miniprogram directory	WeChat DevTools; the public project uses touristappid
WeChat phone preview	Follow the test-account instructions	An assigned test AppID or registered AppID with developer access

The mini-program package is a developer test kit. A shared WeChat trial QR code requires an uploaded trial build and tester permissions; this release does not include a public trial QR code.

Features

• General solid-solute calculations, with AgNO₃ and HAuCl₄ anhydrous/trihydrate presets.
• Mass → final volume and final volume → mass, with mg/g, mL/μL and mmol/L/mol/L.
• Common concentration templates, editable general molar mass and solvent presets.
• Copy preparation steps, reset the form and retain local recipe history.
• Optional pure-solvent equivalent estimates from density and molar mass.
• English interface, responsive browser layout and local calculations.

A quick check

For AgNO₃ with a molar mass of 169.87 g/mol:

• 169.87 mg at 10 mmol/L gives a final solution volume of 100 mL.
• A final volume of 10 mL at 10 mmol/L requires 16.987 mg.
• HAuCl₄·3H₂O at 10 mmol/L and a final volume of 10 mL requires 39.383 mg, using the packaged 393.83 g/mol preset.

The calculation is $n=m/M$, $V=n/C$ or $m=CVM$. Here $V$ is final solution volume, not an instruction to add that entire volume of solvent. Dissolve the solid in less solvent, then make up to the target volume.

Confirm the reagent form, molar mass and intended preparation procedure against the actual reagent label. Pure-solvent estimates are illustrative and temperature dependent; they do not determine the exact solvent addition or solution density. This preview covers solid-solute molarity calculations, not stock dilution or solubility prediction.

Local development

No package installation is required. Node.js 20+ runs the tests and packaging helpers; Python is optional for a local HTTP preview.

git clone https://github.com/RobinMAJ/SolutionPrep.git
cd SolutionPrep
node scripts/build.mjs
node --test
python3 -m http.server 8876 --bind 127.0.0.1 --directory docs

Open http://127.0.0.1:8876/. web/calc.js is the shared calculation source. The build helper copies it to miniprogram/utils/calc.js and prepares the static /docs site. After changing calculation logic, run the build and tests together.

Project layout

Folder	Purpose
web/	Browser source and calculation tests
miniprogram/	Sanitized WeChat DevTools project
docs/	Generated static site for GitHub Pages
guides/	Testing, calculation and release notes
tests/	Mini-program behavior checks
scripts/	Reproducible local build and release packaging

Privacy and testing status

Calculation inputs stay in the browser or mini program. The application has no calculation backend, analytics or cloud synchronization. Browser history is saved explicitly on the device; the mini program keeps the latest 50 copied recipes in local WeChat storage.

This is Preview v1.0.0. See validation for arithmetic checks, browser checks and the limits of mini-program testing. Private WeChat configuration, the original AppID, Xcode user settings and local research files are excluded from the public package.

Original code and documentation are MIT licensed. Author: Jiabin Ma. Personal website · GitHub