molarity of HCl
RUTH MCMAHON
In my lab we cannot agree on the molarity of the following solution.
On a bottle of concentrated HCl is the following information,
mw = 36.36
1.19kg = 1L
37%.
There are conflicting views of
10.15M
11.2M
12.01M.
Could someone please explain the correct way of calculating this.
Thankyou.
Ruth.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Ruth McMahon, PhD., Tel: 706-2815
Biotechnology Centre, Fax: 269-2016
University College Dublin,
Belfield,
Dublin 4,
Ireland.
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Petr Kuzmic
RUTH MCMAHON wrote:
>
> In my lab we cannot agree on the molarity of the following solution.
> On a bottle of concentrated HCl is the following information,
> mw = 36.36
> 1.19kg = 1L
> 37%.
Ruth, missing piece: "37%" is "37%(w/v)", meaning 370 g/L.
Thus c ~ 12M.
Get "CRC Tables for Chemistry and Physics" if you don't have them
_____________________________________________________________
Petr Kuzmic Ph.D. * BioKin Ltd. * Madison, WI 53708-8336, USA
pku...@biokin.com * http://www.biokin.com * 608.256.1269 fax
Harold V. Taylor
RUTH MCMAHON wrote:
>
> In my lab we cannot agree on the molarity of the following solution.
> On a bottle of concentrated HCl is the following information,
> mw = 36.36
> 1.19kg = 1L
> 37%.
>
the correct way of calculation is:
Density = 1.19 kg/l thus you have 1190 g per l. Of these 1190 g per
liter, 37% (or 1190 * 0.37 = 440.3 g) are HCl. By dividing 440.3 g/l of
HCl by the molecular weight of HCl (36.36 g/mol), it is possible to
calculate the molarity of your solution: 440.3 g/l / 36.36 g/mol =
12.11 mol/l.
Have fun,
--
Harold V. Taylor
Physiol. Chem. Institut
Hoppe-Seyler-Str. 4
D-72076 Tübingen
phone: 07071-297-3353
fax: 07071-29-3361
email: cbi...@uni-tuebingen.de
Alejandro Krimer
Dear Ruth:
Remember tht molarity is expressed in mol of HCl/liter of
solution.
The correct way is:
1 liter- 1.19 Kg - 1190 g of solution
HCl is 37 % --- 1190*37/100 = 440.3 g of HCl
If MW is 36.36, we have 440.3/36.36 = 12.11 mol HCl/liter of
solution
This is the molarity
Hope help you!
> ----------
> From: RUTH MCMAHON[SMTP:rmcm...@ollamh.ucd.ie]
> Sent: Saturday 18 de October de 1997 16:57
> To: met...@net.bio.net
> Subject: molarity of HCl
>
> In my lab we cannot agree on the molarity of the following solution.
> On a bottle of concentrated HCl is the following information,
> mw = 36.36
> 1.19kg = 1L
> 37%.
Robert M. Mihalek
In article <344B88...@physik.mu-luebeck.de>
Thomas Hettmann <hett...@physik.mu-luebeck.de> writes:
> Let's start with the 37%. If nothing else is specified, that means
> weight per weight, i.e. 370 g of HCl per 1 kg of solution.
Is weight per weight really the default unit? I was under the
impression, though I've never read the official rules anywhere, that
weight per volume was the default unit. Most replies to this post seem
to believe that 37% specifies weight per volume, not weight per weight.
Bob Mihalek,Ph.D. University of Pittsburgh
remove NOSPAM. for non-commercial e-mail replies
David F. Spencer
In article <62niqp$p...@usenet.srv.cis.pitt.edu>,
mih...@NOSPAM.smtp.anes.upmc.edu (Robert M. Mihalek) wrote:
> In article <344B88...@physik.mu-luebeck.de>
> Thomas Hettmann <hett...@physik.mu-luebeck.de> writes:
>
> > Let's start with the 37%. If nothing else is specified, that means
> > weight per weight, i.e. 370 g of HCl per 1 kg of solution.
>
> Is weight per weight really the default unit? I was under the
> impression, though I've never read the official rules anywhere, that
> weight per volume was the default unit. Most replies to this post seem
> to believe that 37% specifies weight per volume, not weight per weight.
Concentrated hydrochloric acid is approximately 37 weight percent (37%
weight/weight) which is why the density of the solution is critical to
determining the molarity (moles/litre). This seems to be the standard way
of designating the stock concentrations of inorganic acids (phosphoric
acid, nitric, hydrobromic, perchloric, etc. are all sold by weight %).
Formaldehyde and ammonium hydroxide are also sold as weight per cent
solutions.
Dave
--------------------------------------------
David F. Spencer, PhD
Dept. Of Biochemistry
Dalhousie University
Halifax, Nova Scotia
Canada
Peter
In article <01bcde67$b68ca680$81e3...@host.telepac.pt>, "Vitor Cruz"
<vito...@mail.telepac.pt> wrote:
> After reading 3 different answers, all of them correct but nevertheless
> different, I would like to express another point of view:
>
But there is only one correct answer and all were not correct.
Appearances are decieving. Now let's go back in time to GENERAL CHEMISTRY.
First HCl is a strong acid and completely ionizes in aqueous solutions and
chemists do not use the stupid percent values(g/100ml) because a percent
should have no label and this number obviously has a label. But now I
digress.
- HCl has a MW of 36.5 and a specific gravity of 1.19 g/ml
- the percent on the bottle refers to w/w and is usually 37% but different
lots may vary from 36.5% - 38%.
- for all the biologists out there the percentage(g/100ml) is 44 %.
- the approximate molarity is 12.1 M. Note that I only have three sig
figs because this was calculated by the real pecent on the bottle (w/w).
NOW kill this thread. This is getting very silly
Peter
--
"Don't you eat that yellow snow
WAtch out where the Huskies go"
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