|MadSci Network: Chemistry|
You are halfway there... you are looking down all the right paths. Step one: get your hands on a regular chem book and/or the _CRC handbook of Physics and Chemistry_. Both have tables of Ksp. In the chem book look under Ksp. In the CRC, look up "solubility product constants" (which is what Ksp stands for) and "solubility salts, chart or in selected solvents". I checked the Ksp table real quick in my edition of the CRC... some of your salts aren't in there. This makes sense however, since Ksp's are usually only calculated for slightly soluble salts and if any of your salts are better than "slightly soluble" they probobly don't have a Ksp. Step two: Look for those compounds in the CRC in the big table of Physical Constants of Inorganic Compounds... you will find all the information. This is in the front of the "B" section of the CRC. If you've never used a CRC, just open it up and start browsing. The page numbers will start to make sense. Anyway, once you've found the Physical Constants of all your compounds... especially "solubilty in grams per 100 cc" (which translates to 'how many grams dissolve in 100 ml of water) compare "cold water" to "hot water." This will help you figure out whether their solubility increases with the water temperature or decreases. Generally, the warmer the water, the better a solid dissolves, and the worse a gas dissolves. But I will emphasize this is only USUALLY true. In fact I spot one exception to that rule in your list right away. I will walk you through a compound not in your list to give you an example to work with: MnSO4 - in the cold water column there is a "52" with a little "5" superscript. This means that 52g of MnSO4 dissolve in 5 degree celcius water. in the hot water column there is a "70" with a little "70" superscript. This means that 70g of MnSO4 dissolve in 70 degree C water. That means that as the water gets warmer, more manganese (II) sulfate dissolves. If you were to go by Ksp, you would compare Ksp's of the different chemicals. The smaller the number (the more negative the exponent) the less soluble something is. Ksp's in tables are usually only at 25 deg. C and so would not be helpful for determining different solubilities at different temperature... but they are helpful in determining comparative solubilities at a single temperature. I'm not going to go into an explanation of Ksp here... becuase I'm not sure if you needed one. Further, I am afraid a quickly typed explanation might confuse more than it helps. If this is a science assignment, your teacher sounds like one sharp cookie - and could probobly give you any more expalnation regarding Ksp that you need. Good Luck! I hope this helps. Oh yes, if you can't get your hands on a CRC at school ask at the reference desk of your school or local library. Both really should have one. Greta Hardin
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