ChemTrix Chemistry Calculator for iPhone – Chemistry App Review

I have downloaded the app ChemTrix Chemistry Calculator by Black Rhino for the iPhone ( while it was briefly free in the appstore. It is currently listed for $3.99 CAD. It has been evaluated on an iPad mini.


First Impressions:

The ChemTrix Chemistry Calculator iphone app is exactly as the name advertises, an app to calculate typical chemistry values.



All undergraduate chemistry courses require that some fundamental calculations are performed, both in the lecture and lab. Most calculations are fairly straight forward, as long as students possess the basic skills of unit conversion (dimensional analysis).


The App:

It can calculate things like molecular weight, monoisotopic weight, percent composition (by mass) and convert between grams and moles. It is fairly intuitive and easy to use, like a normal calculator, just punch in the number of each element in the molecule and hit enter to view the molecular weight and percent composition.
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At first it appears that you can only choose from some of the more common elements (C, H, N, O, P, S, Cl), but a swipe from right to left gives a complete alphabetical list. As well, it lists a surprisingly large number of commonly used organic groups, ions, ligands and the history of your previous calculations. Embarrassingly, this swipe feature eluded me at first! When in doubt, carefully consult the help menu or contact the Black Rhino support team, who were very quick to respond to my query. I have also been informed that if  ChemTrix is run on a 4″ iOS device,  a row of four programmable buttons will also be available (this review was performed on an iPad mini).

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Tap on the formula again and it opens up the mass/moles/molar mass converter where you can enter a mass or number of moles to convert between the two. There is also a concentration calculator, allowing you to determine the concentration.


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The units can be changed between 4 SI prefix options (eg. mol, mmol, µmol and nmol).

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However, this app is fairly limited, as you can only choose 7 of the more common elements (C, H, N, O, P, S, Cl), which may work for many simple organic molecules, but that is about it. You can select certain R-groups (like methyl, ethyl, phenyl etc.)


I was disappointed in the “Mass Distribution” plot, as there are no axis present. For example, I put in the simple molecule C2H3Cl: Chlorine has two common isotopes 35C and 37C, in a roughly 3:1 ratio. Therefore a signal should be present at approximately 62 and at 64, in a 3:1 ratio. This is not clearly shown in the spectrum provided below, but can be found by clicking upon it to pull up a peak intensities menu.

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A help menu is available and is well written.

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Final Impressions:

Overall, this app can quickly determine molecular weight and perform some conversions, and has a surprisingly large amount of groups, ions and ligands programmed in. However, the conversions it can perform could be done fairly quickly by a relatively competent grade 11 student with a calculator, pen and paper. There is an iPad version of ChemTrix available, which appears to have expanded functionality, but I know many of my students use their iPhones (as a calculator particularly for quick calculations). I will be reviewing the iPad version in the near future.



The author downloaded the software from the app store while it was briefly free, and received no other compensation.

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