Chemical Forums

Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: krknn on November 18, 2022, 06:00:13 PM

Title: Help with adjusting and calculating molar ratios of SiO2 and Na2O
Post by: krknn on November 18, 2022, 06:00:13 PM

Hi! I’m a non-chemist (very much a beginner in chemistry) designer working with ceramics and mineral-based materials. I’ve run into a problem with calculating a recipe, and it would be great if somebody could help.

Here’s the problem in as short as possible. I am using two ingredients:
- sodium silicate (26% SiO2, 7,5% Na2O and 66,5% H2O)
- sodium hydroxide, NaOH
Currently the molar ratio of SiO2:Na2O is around 3.36:1, if I’m not entirely mistaken. I would need to adjust the ratio to around 1.7:1 by adding NaOH. However, as sodium in NaOH is just Na, and not the same Na2O, and also contains hydrogen, I don’t know how to calculate that. How does this work?

The amounts and ratios change throughout my project, so what I’m looking for is a formula to use for replicating the calculations with different values. So not only the end result with these particular values.

I would be grateful if anyone could explain this, thank you!

Title: Re: Help with adjusting and calculating molar ratios of SiO2 and Na2O
Post by: Borek on November 19, 2022, 03:44:00 AM

Would treating NaOH as Na₂O·H₂O help?