Now you are in the subtree of Physics public knowledge tree.

Physics units and constants

http://www.astro.wisc.edu/~dolan/constants.html

https://ned.ipac.caltech.edu/level5/Glossary/lang_formulae.html

relations

https://en.wikipedia.org/wiki/Bohr_radius

https://en.wikipedia.org/wiki/Fine-structure_constant

conversions

https://www.unitsconverters.com/en/Hertz-To-Kelvin/Unittounit-3511-3514?MeasurementId=15&From=3511&To=3514

https://physics.nist.gov/cuu/Units/prefixes.html

PPM - parts per million

moles to grams

https://sciencing.com/determine-moles-chemistry-8561700.html

https://www.softschools.com/formulas/chemistry/moles_to_grams_conversion_formula/111/

https://www.online-calculator.com/scientific-calculator/