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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: denisa174 on March 17, 2021, 04:47:43 AM

Title: Mass concentration
Post by: denisa174 on March 17, 2021, 04:47:43 AM

What is the molar concentration and mass concentration of 97% formic acid, ρ = 1,22 g/l, M = 46,03 g/mol?

Molar concentration c_n = (w ∙ ρ)/M = (0,97 ∙ 1,22)/46,03 = 25,7 mol/l.

Am I right that mass concentration is c_m = c_n ∙ M = 25,7 ∙ 46,03 = 1183,4 g/l
or easily c_m = w ∙ ρ = 0,97 ∙ 1,22 = 1183,4 g/l?

Is it ordinary to calculate mass concentration of a liquid acid?

I have to say I really hate mass concentration, but my colleagues use only this and now I'm really confused.

Thanks for any help

Title: Re: Mass concentration
Post by: chenbeier on March 17, 2021, 06:41:29 AM

In your calculation you used a wrong specific gravity. It is only 1,22 g/ml and not 1.22 g/l. But somehow you got the right result.
Yes in acids,  basic and salt solution the mass concentration %w.w is used. For alcohol for example its % v/v.