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[Spliknot13]

Hi, our exams finally ended. But after talking to my classmates after the exam I was confused and felt frustrated in this problem:

 

Glauber's salt is to be made in a Swenson Walker crystallizer by cooling a solution saturated at 30 C to 15 C. Cooling water enters at 10 C and leaves at 20 C. The overall heat transfer coefficient in the crystallizer is 25 BTU/hr ft^2 F and each foot of crystallizer has 3 squre feet of cooling surface. a. How many 10 units of crstallizer will be required to produce 1 ton of Glauber's salt? ( Determine the amount of cooling water in gal/min Data: Latent heat of crystallization = 18000 cal Gmole Glauber's salt Specific heat of solution = 0.714 Btu/lb F.

 

by the way Glauber's Salt is Na2SO4x10H20

my question is that in perrys it is stated in the solubility table that

"This table shows the amount of anhydrous substance that is soluble in 100 g of water at the temperature in degrees Celcius. Solid Phase gives the hydrated form in equlibrium with the saturated solution"

 

So the question is for example if the substance is Na2SO4  with a solid phase as Na2SO4x10H20 @ 20 C it shows that the solubility is 19.4. Is the 19.4 g Na2So4 or Na2So4x10H20? cause I believe that its 19.4 g Na2So4 cause that's how I understood the description in the table. Can someone help me clarify this? Thanks in advance

[latexman]

To me, it means 19.4 g of anhydous Na2SO4 in 100 g H20.  If one molecule of anhydous Na2SO4 is added to the saturated solution, Na2SO4x10H20 starts to precipite out of solution.

 

It also seems to me you need the solubility at 15 C according to your problem statement.

Edited by latexman, 11 September 2013 - 10:02 AM.