Randy's thoughts on trace elements

[Randy Holmes-Farley Verified Community Expert]

Thanks a lot @Randy Holmes-Farley . Just wanted to double check.
Where do you check the weight of the individual elements? Is there a book or a web page?
Cause if i simply goodle it i get 45.5% ( please see screenshot attached)
just want to learn how to check those things properly

Another example of an AI fail. They are not reliable. It neglected the water mass in the structure.

In addition to Hans-Werner went about it, here's a slightly different way I do it, but there are many ways, including working it all out using a "periodic table" that if you google it gives weights for every element.

If you have an exact name for the chemical, such as strontium chloride hexahydrate, google just exactly those words, with an mw in front

"strontium chloride hexahydrate"

The first hit is a chemical company selling it, and they will reliably give the molecular weight (mw) correctly. In this case, 266.62

https://www.sigmaaldrich.com/US/en/...db-W1vEOXVHNdOWljCw2rE7h97Y2vDieKJHRlROJMEMDl
then google just the element of interest with the letters mw in front of it

"mw strontium"

That gives the molecular weight of strontium (87.62).

The percentage of the material that is strontium is thus 100% x 87.62/266.62 = 32.9%.

The only complexity is if the original formula includes more than one of the element that you are asking about. The structure shown on the chemical company page will tell you. Our material here has only one strontium, but some might have more than one, such as sodium carbonate (Na2CO3) having two sodium atoms and three oxygen atoms. If you were asking about the percentage of sodium in sodium carbonate, you'd need to multiple the sodium molecular weight by two, before dividing by the Na2CO3 molecular weight.

 

[Hans-Werner]

The first hit is a chemical company selling it, and they will reliably give the molecular weight (mw) correctly. In this case, 266.62

In analogue times as the Merck catalogue was still in print (>25 years) I used the Merck catalogue and made notes at the most interesting compounds. I still have one and sometimes, when I have to check a number of compounds, I still use it. Browse through the pages of the catalogue may still be quicker than browsing the internet.

 

[acro_lover]

That's way more than i was hoping for. Thank you so much @Lasse , @Randy Holmes-Farley and @Hans-Werner for looking into my question and educating me. Now i know how to try to work out those things on my own. I might still need to double check though :) at least at the beginning. Thank you.

 

[Randy Holmes-Farley Verified Community Expert]

I might still need to double check though :) at least at the beginning. Thank you.

Certainly. :)