🧪 Solutions Calculator

This Shiny app allows you to perform basic chemical calculations based on molarity, mass, volume, and molecular weight. It retrieves molecular weights from PubChem using the webchem package.

🚀 Features

Users can select from three calculation modes:

1. Mass
   Calculates the amount of substance (in grams) from a given volume and concentration.

2. Volume
   Determines the required volume (in mL) to obtain a given mass at a specific concentration.

3. Molarity
   Computes molarity (mol/L) from mass and volume.

🧮 How It Works

• The user enters the name of a compound (e.g., glucose, caffeine).
• The app uses the webchem package to search PubChem for its molecular weight.
• The user inputs two of the following: mass, volume, or concentration.
• The app calculates the third value based on the selected mode.

💻 Tech Stack

• R and Shiny
• webchem for retrieving molecular weight from PubChem
• shinythemes for styling
• renv for project-specific package management and reproducibility

📦 How to use

To run the app locally, make sure you have R and the following packages installed:

install.packages(c("shiny", "webchem", "shinythemes"))

🧪 Example

Try entering:

• Compound: glucose
• Calculation mode: Mass from volume and concentration
• Concentration: 1 mM
• Volume: 1 mL

Output:

• Mass = 0.18016 g (based on glucose molecular weight ≈ 180.16 g/mol)

📄 License

MIT License. Feel free to use, modify, or distribute this project.

✍️ Citation

Jesica Formoso, & karina formoso. (2025). JFormoso/solutions_calculator: v1.0.1 (v1.0.1). Zenodo. https://doi.org/10.5281/zenodo.15226728

🙋‍♀️ Acknowledgments

This app uses open data provided by PubChem via the webchem package, maintained by ropensci.

Szöcs E, Stirling T, Scott ER, Scharmüller A, Schäfer RB (2020). “webchem: An R Package to Retrieve Chemical Information from the Web.” Journal of Statistical Software, 93(13), 1–17. doi:10.18637/jss.v093.i13.