Strategies for Determining Solubility and Hydration in Chemistry

[ACLerok]

I need some quick bits of info regarding solubility. How do I determine whether one substance is more or less soluble than another substance? I know to look at the solubility rules but other than that, what characteristics and properties should I be looking at? Also, how do I determine between two substances how soluble antoher substance will be? For instance, would boric acid be more soluble in ethanol or in benzene? And I know that the larger the ion, the lower the energy of hydration but what about Mg2+ and Al3+?

 

[gravenewworld]

I'm sure you have heard the phrase "likes dissolve likes". This is a very good way to get an idea of whether something will be soluble in another substance. For example oil and water obviously do not mix, water is a polar molecule while the oil is some non polar hydrocarbon. Water and say ethanol will mix because ethanol is a polar molecule like water. If you are talking about solids dissolving in some solvent then you will want to look at their Ksp values.

 

[Rampantbaboon]

Well, if something is considered soluble there are plenty of charts plotting solubility in some unit or another with temperature. Immulcifiers(sp) are usually large molecules with a polar and non-polar part that can dissolve both. Examples are soap for dissolving grease and then being able to be washed of with water, or flour when making gravy by getting the water and fat into a relatively stable colloid. The Ksp tables will also be a big help. There are some that are odd such as Ca(OH)2 that often skirt the line...that you will generally just need an outside resource for information. If you have access to the chemistry and physics handbook, or something or other like that, I'm sure it will have more than enough information