FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups 
 ProfileProfile   PreferencesPreferences   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Forum index » Science and Technology » Chem
pH Calculation
Post new topic   Reply to topic Page 1 of 1 [5 Posts] View previous topic :: View next topic
Author Message
Borek
science forum Guru Wannabe


Joined: 02 May 2005
Posts: 157

PostPosted: Sat Jul 01, 2006 8:16 am    Post subject: Re: pH Calculation Reply with quote

On Fri, 30 Jun 2006 23:14:35 +0200, omicron <info99@ptd.net> wrote:

Quote:
Concentrated HCL is 38.7% mass percentage and 12.1 molar (I believe
that is accurate).
Therefore, using arithmetic, if I dilute it (v/v) by taking 129 ml and
bringing the final volume to 1000ml, I should have approximately a 5%
solution. The math:
1000/129 = 7.75
38.7% / 7.75 = 4.99% or 5%
Correct so far?

In the first post you have stated you HAVE 5% solution - why do you try to
dilute some other solution now? Just convert % to molarity, as described
here:

http://www.chembuddy.com/?left=concentration&right=percentage-to-molarity

Quote:
If so, then the molarity of the concentrated acid is also cut by the
7.75. The math here:
12.1 M / 7.75 = 1.56 M, so the molarity of a 5% HCL solution is
approximately 1.56M.
Also correct??

No, such approach will work only if the density of all solutions is
identical - it is not.

Best,
Borek
--
http://www.chembuddy.com
http://www.ph-meter.info/pH-measurements-indicators
http://www.terapia-kregoslupa.waw.pl
Back to top
omicron1
science forum beginner


Joined: 30 Jun 2006
Posts: 2

PostPosted: Fri Jun 30, 2006 9:14 pm    Post subject: Re: pH Calculation Reply with quote

Hello Ricahrd,
Thank you for your reply.
Allow me to try your idea:
Concentrated HCL is 38.7% mass percentage and 12.1 molar (I believe
that is accurate).
Therefore, using arithmetic, if I dilute it (v/v) by taking 129 ml and
bringing the final volume to 1000ml, I should have approximately a 5%
solution. The math:
1000/129 = 7.75
38.7% / 7.75 = 4.99% or 5%
Correct so far?
If so, then the molarity of the concentrated acid is also cut by the
7.75. The math here:
12.1 M / 7.75 = 1.56 M, so the molarity of a 5% HCL solution is
approximately 1.56M.
Also correct??
Assuming your answer to both my questions is YES, I've completed the
first part of your roadmap answer to my original question.
Please let me know if I'm on the correct path and, if so, I'll then
tackle the 2 and 3 portion of your answer.
Thank you again!





Richard Schultz wrote:
Quote:
In article <1151638294.571462.58760@x69g2000cwx.googlegroups.com>, omicron <info99@ptd.net> wrote:
: Can someone show me how to calculate the pH of a 5% Hydrochloric acid
: solution?

(1) What is the *molarity* of a 5% HCl solution?
(2) Assuming that the HCl is completely dissociated, what is the concentration
of H+ ions in a 5% HCl solution?
(3) What is the relation between the H+ concentration of a solution and its
pH?

-----
Richard Schultz schultr@mail.biu.ac.il
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
Opinions expressed are mine alone, and not those of Bar-Ilan University
-----
"an optimist is a guy/ that has never had/ much experience"
Back to top
Borek
science forum Guru Wannabe


Joined: 02 May 2005
Posts: 157

PostPosted: Fri Jun 30, 2006 12:11 pm    Post subject: Re: pH Calculation Reply with quote

On Fri, 30 Jun 2006 05:31:34 +0200, omicron <info99@ptd.net> wrote:

Quote:
Can someone show me how to calculate the pH of a 5% Hydrochloric acid
solution?
I need to do it with no equipment or test papers.
Any help would be greatly appreciated.

http://www.chembuddy.com/?left=pH-calculation&right=pH-definition

http://www.chembuddy.com/?left=pH-calculation&right=pH-strong-acid-base

http://www.chembuddy.com/?left=BATE&right=pH-cheat-sheet

Best,
Borek
--
http://www.chembuddy.com
http://www.ph-meter.info/pH-measurements-indicators
Back to top
Richard Schultz
science forum Guru


Joined: 28 Apr 2005
Posts: 339

PostPosted: Fri Jun 30, 2006 3:47 am    Post subject: Re: pH Calculation Reply with quote

In article <1151638294.571462.58760@x69g2000cwx.googlegroups.com>, omicron <info99@ptd.net> wrote:
: Can someone show me how to calculate the pH of a 5% Hydrochloric acid
: solution?

(1) What is the *molarity* of a 5% HCl solution?
(2) Assuming that the HCl is completely dissociated, what is the concentration
of H+ ions in a 5% HCl solution?
(3) What is the relation between the H+ concentration of a solution and its
pH?

-----
Richard Schultz schultr@mail.biu.ac.il
Department of Chemistry, Bar-Ilan University, Ramat-Gan, Israel
Opinions expressed are mine alone, and not those of Bar-Ilan University
-----
"an optimist is a guy/ that has never had/ much experience"
Back to top
omicron1
science forum beginner


Joined: 30 Jun 2006
Posts: 2

PostPosted: Fri Jun 30, 2006 3:31 am    Post subject: pH Calculation Reply with quote

Can someone show me how to calculate the pH of a 5% Hydrochloric acid
solution?
I need to do it with no equipment or test papers.
Any help would be greatly appreciated.
Thank you.
Back to top
Google

Back to top
Display posts from previous:   
Post new topic   Reply to topic Page 1 of 1 [5 Posts] View previous topic :: View next topic
The time now is Thu Oct 18, 2018 9:31 am | All times are GMT
Forum index » Science and Technology » Chem
Jump to:  

Similar Topics
Topic Author Forum Replies Last Post
No new posts load flow calculation BVU Control 0 Thu Jul 20, 2006 5:05 am
No new posts Advanced analytical methods for path integral calculation jaykov1 Particle 0 Tue Jul 11, 2006 2:36 am
No new posts Advanced analytical methods for path integral calculation. jaykov1 num-analysis 0 Sat Jul 08, 2006 11:36 pm
No new posts Profit margin calculation wheel shareyourknowledge@hotmai Math 0 Mon Jul 03, 2006 12:19 am
No new posts Eigen Vector Calculation Shailesh Math 0 Thu Jun 29, 2006 3:09 pm

Copyright © 2004-2005 DeniX Solutions SRL
Other DeniX Solutions sites: Electronics forum |  Medicine forum |  Unix/Linux blog |  Unix/Linux documentation |  Unix/Linux forums  |  send newsletters
 


Powered by phpBB © 2001, 2005 phpBB Group
[ Time: 0.0152s ][ Queries: 20 (0.0030s) ][ GZIP on - Debug on ]