solubility curves

Wow, many of you are back from Spring Break – I hope you're well rested and ready to finish your school year!

There isn't money left in most 2014-2015 science department budgets this late in the school year.  For inexpensive chemistry lab ideas, buy my lab book Chemistry on a Budget for $20.56 at amazon.com or $23 at lulu.com. It will take a few weeks to get to you, so order now! 

http://www.amazon.com/Chemistry-Budget-Marjorie-R-Heesemann/dp/0578129159/ref=sr_1_1?s=books&ie=UTF8&qid=1389410170&sr=1-1&keywords=chemistry+on+a+budget

http://www.lulu.com/shop/marjorie-r-heesemann/chemistry-on-a-budget/paperback/product-21217600.html

This book contains 13 labs using consumable materials purchased from local stores.  There are two versions of each lab, one with a ten-question conclusion and one with directions for a full lab report.  This way the teacher has the option!  Each lab is two pages to allow for one two-sided handout.  

I previously posted several pages about Solutions – on 3/19/14 Properties of Solutions, 3/23/14 Molarity, and 3/26/14 Vapor Pressure, BP/FP, and Molality.   

All three posts contain a lot of information – if you haven’t viewed them, you might want to check them out!  

Today, I’m going to focus on the Solubility Curve, a typical topic for Introductory Chemistry courses.  

One definition is:
·  Definition of SOLUBILITY CURVE. : a graphic representation of the variation with changing temperature of the solubility of a given substance in a given solvent.
www.merriam-webster.com/dictionary/solubility%20curve

From my 3/19/14 blog post:  

The information of several solutions can be contained on a solubility curve, which is a graph of grams of solute (y-axis) dissolved in 100 g of solvent versus temperature (x-axis).  Most of the lines are increasing (solid solutes) but sometimes the line is decreasing (gas solute).

Here is an image that shows how a solubility curve can be read, that the line plots the saturated solution, any point below is an unsaturated solution, and any point above the line would be for a supersaturated solution.

Here's one sample of a Solubility Curve:
http://schools.birdville.k12.tx.us/cms/lib2/TX01000797/Centricity/Domain/912/ChemLessons/Lessons/Solutions/image003.jpg

This is a skill students master quickly – one twist in questions to increase difficulty could be changing the amount of solvent to prepare the solution (resulting in a changed solution concentration).  

This worksheet has a Solubility Curve page and the answers!

http://www.canogaparkhs.org/apps/download/vGqaBxVBFHzx7biSUWQ0aQAUY9CRTzObT1jisiS0upetMWoV.pdf/Solubility%20Curve%20Worksheet.pdf


This link has several pages of questions and Solubility Curves on some of the pages:

http://www.nhvweb.net/nhhs/science/bklingaman/files/2012/08/13.2-Solubility-Curve-Worksheet.pdf

 
This page is two half-page worksheets, so you could save paper; and, it has the Solubility Curve on the page.  It contains 11 questions – perhaps you could use it as a Quiz:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&ved=0CB0QFjAAOAo&url=http%3A%2F%2Fimage.epsilen.com%2FDownload%2FDownloaderPopup.aspx%3FfileID%3Df3T8Mc4ACls%3D%26hostUserAccountID%3DJ7cIzuqGsYE%3D%26isPublic%3DGt9CW5WreOc%3D%26SessionHostUserAccountID%3DJ7cIzuqGsYE%3D%26SessionHostID%3D%2F9hBT3OGLJo%3D%26SessionWebsiteID%3D4MUhihjA9p4%3D&ei=FHUuVZiEOJTbsATorYHYAw&usg=AFQjCNHtepwK5SIhwb8tLUYh_wEV3HAj3g&bvm=bv.90790515,d.cWc

 
This link is just 2 pages, questions and a Solubility Curve, for easy photocopying (one 2-sided page):

http://www.leydenscience.org/pswp2/Gen%20Fun/Unit%208%20&%209/Solubility%20Curve%20WS.pdf

 
Typical labs for the Solubility Curve is to prepare a Curve from student data.  Check in your department to see what has been done.

Here’s a quick video to provide an ov

You may not have pipets available for student use – graduate cylinders could be used.

Instruct your students to be careful when stirring with the thermometer!  Stir in a circular fashion – up and down could accidentally break the test tube!  

Here’s one lab that also plots the correct values and instructs to draw the graph in a different color for easier comparison:

http://www2.ucdsb.on.ca/tiss/stretton/chem1/lab8.html

You may have to Copy and Paste it to print it out – it is 2 pages.

 
Here’s another 2-page lab:

http://www.rocklin.k12.ca.us/staff/avrudny/science/Chemistry/Unit_5/2012Wksht_Solubility_of_a_Salt.pdf


If you can’t get potassium nitrate (KNO3), here’s a lab using sugar in water:

http://haydukchemistry.weebly.com/uploads/2/0/9/7/20974360/lab_solubility_curve_of_sugar.pdf

I like that it’s only one page!
 

Remember, you can check out the Topic List to help you to find past Blog entries.


Have a good weekend!