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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Bevswg04 on February 11, 2008, 09:45:20 PM

Title: Question about Specific Heat Capicities for Agueous solutions
Post by: Bevswg04 on February 11, 2008, 09:45:20 PM

I have been trying to find the specific heat capacities from different books for 2 M of sodium hydroxide (NaOH), 2 M of hydrochloric acid (HCl), and 2 M of ammonium hydroxide (NH4OH); however, I have unfortunately been able to calculate these values properly from charts.  I believe the values will be close to that specific heat of water (4.184 J/g deg).  If anyone can point me in the right direction of acquiring these specific heat values, I would be most appreciative.

Title: Re: Question about Specific Heat Capicities for Agueous solutions
Post by: enahs on February 11, 2008, 10:48:10 PM

http://en.wikipedia.org/wiki/Hydrochloric_acid#Physical_properties
http://piona.com/customers/tech/data/naoh/SPECIFIC%20HEAT.pdf

Just two quick google results. You have to convert units and interpolate (I would just assume that between 10% and 0% is linear and at 0% HCl it is the specific heat of water). I am sure you can find Ammonium Hydroxide. Though, if you have access to a Handbook of Chemistry (CRC, Langes, etc) it will have them all for sure. You might even have free access online through your schools library.

Title: Re: Question about Specific Heat Capicities for Agueous solutions
Post by: Bevswg04 on February 11, 2008, 11:25:47 PM

Thank you for your help. 

Title: Re: Question about Specific Heat Capicities for Agueous solutions
Post by: ARGOS++ on February 12, 2008, 03:26:36 PM

Dear Bevswg04;

For HCl you may also use, for the range 1.0 %w/w till  16.8 %w/w:   

"Specific Heat capacity question (HCl)? (http://www.chemicalforums.com/index.php?topic=20822.0)”

The corresponding values in kJoule kg^-1 °K^-1 from the top are:  4.096;  4.037; 3.677; and 3.134.

Good Luck!
                    ARGOS⁺⁺

Title: Re: Question about Specific Heat Capicities for Agueous solutions
Post by: ARGOS++ on February 12, 2008, 04:12:50 PM

Dear Bevswg04;

Finally I found also for Ammonium Hydroxide (AH) values!

I found in a “little before yesterday” LANDOLT & BÖRNSTEIN:
(A standard “Book” for such properties.)

AH  +  100 H₂O (= 1.9%w/w = 0.542 molar)  at 18°C  = 4.180    kJoule kg^-1 °K^-1
AH  +    50 H₂O (= 3.7%w/w = 1.056 molar)  at 18°C  = 4.180           “
AH  +    30 H₂O (= 6.1%w/w = 1.743 molar)  at 18°C  = 4.171           “
(The same book up to date would give you much more!)

I hope it gives you not only an Idea.

Good Luck!
                   ARGOS⁺⁺