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Mass calculator

This tool lets you calculate the molecular mass of a given chemical compound. PocketChemistry will calculate what is called "formula weight", that is, the sum of atomic masses for all atoms in the compound.

To calculate the mass, enter the formula into the space provided. The mass will be updated every time you change the text.

You do not have to explicitly capitalize chemical symbols that you use. If you use the calculator in high school only, I doubt you will ever need to enter capitals. To read more about how PocketChemistry capitalizes formulas, see Automatic capitalization.

Syntax of formulae

Each formula may consist of letters, numbers and brackets. You can use capital or lowercase letters (see Automatic capitalization) to enter the elements. No spaces are required between different elements. Brackets can be nested to any reasonable depth (limited by system resources), but it's highly unlikely that you will ever need to use more than one level.

A few things are not supported. You cannot enter composite formulae using the dot (like CuSO4 · 5 H2O). Ions are not supported either. I may add support for composite formulae.

Why error messages flash

As you enter the formula, the text under the formula box keeps changing, telling you about some kind of error. That is a result of trying to calculate the mass every time you change the formula.

An alternative way to implement this tool would be to provide a "Calculate" button. But that would mean you would have to press the button every time after you've entered the formula. Considering how fast the calculation is, I think the tool is easier and faster to use this way. It may take a bit of getting used to ignoring the messages until you have finished entering.

Troubleshooting molecular mass

I have tried to explain all errors right under the formula box, so there is no reason to repeat that here. Email me if I left something out (see Contact details).

If you find that you can't make something work (highly unlikely), enter the formula very carefully from scratch, omitting all spaces, and making each element start with a capital letter. Email me if you still can't make it work and I will see what I can do.

If you think that the mass for some formula is not calculated correctly, email me, and I will try to figure out where the problem is.

Last updated: 01/07/07 Copyright 2002-2007 Roman Starkov
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