Chemistry

Factors that Affect Solubility



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Before one can talk about the factors that affect the solubility, one needs to to know what exactly "solubility" means.  In several entries (Wikipedia, SolubilityofThings.com, About.com), solubility is defined as the following: the ability of a substance to dissolve.  In the Wikipedia entry, solubility is defined as: the property of a solid, liquid, or gaseous chemical substrance called solute to dissolve in a liquid solvent to form a homogenous solution.  Solution is defined as a homogenous mixture composed of two or more substances.  On the solubilityofthings.com website, solubility is defined as the maximum amount of solute that dissolves in a solvent.

Anything that can disolve in a liquid solvent has a high level of solubility.  Depending on the specific substance, you may need a third substance for it to dissolve.  One such example would be oil.  Oil and water together, alone, do not mix.  When you pour a small amount of oil into water and vice-versa, you should see the globs.  In oil, there should be globs of water.  In water, there should be globs of oil.  One major example would be the 2010 oil spill at the BP rig in the Gulf of Mexico.  On the news, it was explained that many solvents were used.  The solvent would be the third factor to make the oil soluble.

In the entry on the About.com website, rules of solubility are introduced.  More specifics are given to water solubility.  

Once one understands the definition of solubility, one can look into the factors that affect it.

In respects to solubility in water, the entry on About.com explains two factors.  The first one talks about the force of attraction between water and the ions of the solid.  If ions are brought into the solution, solubility is rather high.  If the ions are kept in a solid state, the solubility would be low.  

According to the solubility rules, other factors are introduced.  

One factor is if the substance has nitrates (NO3).  Solubility rules say that all nitrates are soluble.  All chlorides are soluble except for AgCl (silver chloride), Hg2Cl2 (mercury chloride), and PbCl2 (lead chloride).  
Most sulfates except for BaSO4 (barrium sulphate), PbSO4 (lead sulphate), and SrSO4 (strontium sulfate), are soluable.  

Except for NH4 (ammonium), all carbonates are not soluable.  One example on how ammonium is soluble is that it is found in urine.  One simply has to watch some of the old Truth About Smoking commercials.  In one commercial, it is explained that one of the substances found in cigarettes is ammonium and it was pointed out that it is also found in urine.

Except for Ba(OH)2 (barium hydroxide) and SR(OH)2 (strontium hydroxide) ,  all hydroxides are not soluable.  But, it is said that Ca(OH)2 (calcium hydroxide) is still soluble.  But, the solubility of calcium hydroxide is very low compared to the other two.

Group 1 and Group 2 element sulfides are soluable.  Those that do not like in those two groups are not soluable.  

In the Solubility of Things website, the factors that affect solubility are the following: temperature, polarity, pressure, and molecular size.  

Pressure plays a factor in respect to gas solutes.  That is explained in "Henry's Law" which was formulated in 1803 by chemist William Henry.  That does not apply to most solids and liquids.  In the Wikipedia entry on Henry's Law, the soft drink is used as an example.  Soft drinks range from your sodas.  

Another example of a solid dissolving in liquid would be hot chocolate.  Temperature plays a very important role.  If the liquid is cold, the cocoa powder probably will not mix as well.  If the lquid is hot, the cocoa powder mixes properly.  Kool-Aid is another example.

On the flip side, temperature affects the solubility of gases.  If the temperature rises, solubility level drops.  If the temperature drops, solubility level rises.  

Mechanically, you can speed up the solubility by stirring.  By stirring, you can make a cup of cocoa or a pitcher of Kool-Aid.  Another example would be mixing flour and eggs to create batter or dough.  


The factors of solubility can be simply explained.  But, one has to consider the substances that are being combined.  One does not necessarily need an expensive chemistry set to test out the solubility of things.  You can easily find stuff in your own kitchen.  You can make soup, milk shakes, ice cream sodas, cakes, and so forth.  Those everyday food and drink items are prime examples on factors that affect solubility.  

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://en.wikipedia.org/wiki/Solubility
  • InfoBoxCallToAction ActionArrowhttp://www.solubilityofthings.com/basics
  • InfoBoxCallToAction ActionArrowhttp://chemistry.about.com/od/solutionsmixtures/a/solubility-rules.htm