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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: rethibaut on January 20, 2021, 02:56:57 PM

Title: HCl density different than 1.2 g/mL when calculated
Post by: rethibaut on January 20, 2021, 02:56:57 PM

Hello everyone,

I'm doing some test for carbonate precipitation for my undergraduate Geology thesis, one of them is using HCl as leachant for some copper slag samples. Due to covid restrictions, my teacher helped me with this, and he weighed slag powder+3mL HCl on a plastic container, at room temperature (22-25°C) and open system.

So for instance, we have this sample, every weight is the median of 5 measurements:

Plastic container: 6.6437 g
Plastic container + Slag powder: 7.7682 g
Container+slag+3mL HCl: 12.5632 g

With that in mind, HCl weight is 4.795 g, so calculated density is 1.6 g/mL, quite far from 1.2 g/mL defined for HCl.

Am I doing some wrong calculation, or maybe I'm not considering a critical factor?

Title: Re: HCl density different than 1.2 g/mL when calculated
Post by: chenbeier on January 21, 2021, 02:16:14 AM

The question is how the 3 ml where measured and taken. Density 1,6 g/ cm^3 is to much.

Title: Re: HCl density different than 1.2 g/mL when calculated
Post by: AWK on January 21, 2021, 02:26:46 AM

This mass corresponds to exactly 4 cm³ of concentrated HCl.

Title: Re: HCl density different than 1.2 g/mL when calculated
Post by: Borek on January 21, 2021, 03:15:04 AM

Note, that it probably doesn't matter much. In typical application where hydrochloric acid is used to dissolve something it should be used in a reasonable excess, and exact amount is not that important.