Page 1 of 1

define the mass from PH

Posted: Thu Jan 07, 2021 8:47 am
by Mohamed4455
-First, I want to make a cup of tea with volum 200ml and PH 6.37
-so, I want to know the concentration of the black tea (powder)
- the concentration is the molarity(M). so, I can know the mass of the tea that I will add to the 200ml of water.(molarity= mass/molar mass/volum)
- but I have a problem, how can I know the molarity from the PH of the tea. PH= (6.37)

Re: define the mass from PH

Posted: Thu Jan 07, 2021 11:23 am
by ChenBeier
Tea is a mixture of hundreds of compounds, so it is impossible to get a molarity.

Re: define the mass from PH

Posted: Thu Jan 07, 2021 12:03 pm
by Mohamed4455
Ok, thanks. but how can I know the concentration (molarity) of a certain substance only from PH?. give me an example, please

Re: define the mass from PH

Posted: Fri Jan 08, 2021 1:42 am
by ChenBeier
You can not, because water and dissociation degree has an influence.
But for strong acids with 100% dissociation like HCl you can astimate.

pH = - log of cH+ ~ cHCl