MadSci Network: Chemistry |
This question isn't as easy as you might think to answer because
solubility is quite a complex concept.
The first thing you should think of is why do chemicals like salt and
baking soda dissolve in water at all, lots of chemicals such as oils do not
dissolve.
An easy rule to remember is "Like dissolves like". Now while you probably
don't know this but chemists think of water as charged, it is made up of
positive and negative charges. This is the reason electricity goes through
water. Now salt, which is really the chemical sodium chloride, is also
charged. Salt is made up of charged sodium atoms and charged chlorine atoms
so these are kind of like the charged water, so thats why salt dissolves in
water.
Baking soda is really the chemical sodium bicabonate and it too is charged,
it is made up of charged sodium atoms and charged bicarbonate molecules, so
it too dissolves in water. Neither salt or baking soda, like water, would
dissolve in oil, as oil is totally uncharged, try this one if you want too.
We determine the solubilty chemicals by looking at the solubility of all
the components of the chemical and working out a "Solubility Product" for
that chemical. So for salt this would look something like this :
Solubility Product of Salt = (concentration of sodium atoms) X
(concentration of chlorine atoms).
So the solubility of a chemical is determined by the solubility of the
molecules and atoms that make up that chemical.
So when it comes to the solubility of salt vs baking soda, this is
determined by how well the salt molecules break up in the water vs how well
the baking soda molecules break up and how well each of the atoms "like"
the water they are in and how much of it dissolves.
In this case salt breaks up more easily than baking soda and the chlorine
atoms from salt interact better with water than the bicarbonate molecules
from baking soda do with water. So salt is more soluble than baking soda.
Well I hope you could understand all that, solubility is a very complicated
topic, that has lots of things to consider, hope my answer was of
assistance.
regards
David Barker
Try the links in the MadSci Library for more information on Chemistry.