define the mass from PH

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Mohamed4455
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define the mass from PH

Post 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)
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ChenBeier
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Re: define the mass from PH

Post by ChenBeier »

Tea is a mixture of hundreds of compounds, so it is impossible to get a molarity.
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Mohamed4455
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Re: define the mass from PH

Post by Mohamed4455 »

Ok, thanks. but how can I know the concentration (molarity) of a certain substance only from PH?. give me an example, please
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ChenBeier
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Re: define the mass from PH

Post 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
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