Factors+Affecting+Solubility

=Factors Affecting Solubility. By AA, EB, and the Dish.=

We felt that, with the group we had as well as the topic assigned, it would be prudent to take a couple minutes to reflect on our roots. We could tell you all about them, thousands of stories about our younger days, but, as they say, a picture is worth a thousand words. This is the Brook. And we, that is to say, me, EB, and Dish, are Brookas for life. We here are the classic examples of east siders. We don't have no huge sprawling rich person housing developments on the east side. We don't got just one huge park on the east side, but instead a multitude of small parks. But we also don't have no run down decaying mall on the east side. See, here on the east side we have character. If our mall was that old and decrepit, we would have it torn down or rebuilt before just leaving it there. In too many ways to name I could speculate on east siders having character in areas that west siders all too often lack. But above all, the east side is a tight knit group with unity. And our unity came from our school, not Central York High School, but the school that taught us all we'd ever need to know to survive in life. Stony Brook Elementary School. The Brook was a unifying force in which by the end of 3rd grade, you knew everyone else in your grade that went to the Brook. And recess at the Brook was legendary, with games of tackle football, kickball, and dodgeball just to name a few. We certainly grew up rough, but nothing in life ever comes easy and the only people who believe that it does are those ignorant pompous fools from the west side. All these good memories that come back to me, it helps to remember where your from. East side for life! Brookas for life! Forever! -AA OUTDOOR STUDY AREA FTW!!! -Nandish
 * //Where we're from...//**

Okay, now we are getting to the meat of the wiki. By this time, we have seen through previous experience that some materials dissolve in other materials, and other materials are practically insoluble in almost all materials. So, we have to take a look at ourselves and say "self, why do some things dissolve and other things sink to the bottom." Well, a major factor in favor of the solvation process is that it increases disorder, or increases entropy. But, there are 3 major factors that really determine a substance's solubility. These 3 factors are solute-solvent attraction, which is to say the bonding and intermolecular forces between the solution contents, pressure, a factor which only takes affect on gases, and lastly, temperature.
 * //Overview//**

The attractive forces between the solute and solvent play an important role in determining the solubility of a substance. For example (from the book), in simple gases, solubility rises with increasing mass in polarity. This is because the main force between gases are London dispersion forces, which I hope you all know by now, increase with the size and mass of a molecule. This would indicate that the solubility of the gas in water increase as the attraction between the solute and solvent increase. And that leads us to our first general statement: **The stronger the attractions between solute and solvent molecules, the greater the solubility.** This is especially true for dipole-dipole attractions between solvent and solute. This is because **polar liquids tend to dissolve readily in polar solvents.** Polar molecules, especially those who can form hydrogen bonds, are soluble in water. Acetone is a great example of this concept because it mixes in all proportions of water because of the strong polar C=O bond and unbound electrons around the Oxygen. Alcohols are a great example of organic compounds that can form hydrogen bonds with water because of the OH bond found in them. Even though alcohols can form hydrogen bonds with themselves and water, they are soluble because of the tendency to move towards chaos.
 * //Solute-Solvent Attractions//**



Pairs of liquids that mix in all proportions, like water and acetone, are **miscible.** Those that do not dissolve in one another are **immiscible.** Gasoline, and other hydrocarbons, are immiscible in water. This is because hydrocarbons are non-polar. The attraction between the water molecules (polar) and the hydrocarbon molecules (gasoline) are not strong enough to form a solution, which is why **non-polar liquids tend to be insoluble in polar liquids.**



So what have we learned from the paragraphs above? **Substances with similar intermolecular forces tend to be soluble in each other.** Non-polar substances are more likely to be soluble in non-polar solvents and ionic and polar solvents are more likely to be soluble in polar solvents.

The solubility of gases, in liquids, like solids in liquids is affected by the forces involved with the solvent and the temperature of the solvent. However, the solubility of a gas in a liquid is also affected by pressure, unlike the solubility of solids and liquids. As partial air pressure of a certain gas is increased around a solvent, more of the gaseous molecules collide with and enter the solution. This also means more molecules will start exiting the solution, so eventually a new dynamic equilibrium will be reached if inside a closed container. (The rate of molecules entering the solution equals the rate of molecules leaving the solution, with more gas molecules dissolved then at the lower pressure. Also explained in the Vapor Pressure page.) The process of gas molecules escaping from a solution is known as effervescence.
 * //Pressure//**

Henry's Law is used to determine solubility of a gas in a solvent:

P = k x C (P) is the partial pressure of the gas, (k) is a constant for Henry's law which is different for every gas, and (C) is the fraction of the gas within a saturated solvent, which can be in moles or various other units.

It states that pressure and Solubility are proportional; If the pressure is doubled without change of temperature, the concentraction of solute molecules dissolved doubles.

( Image from http://itl.chem.ufl.edu/2041_f97/lectures/lec_i.html )

Temperature is a factor with different effects depending on the physical state of the solvent. Therefore, I will split up this section into 2 parts: //Temperature towards solids:// A general statement can be said that the solubility increases with increasing temperature. This increase of solubility is not necessarily linear and follows very little trend when viewing the solubility curves of different substances. However, this general statement is just that, and it is incorrect to make the assumption that ALL solids increase with increasing temperature. However, about 95% of them do. The exceptions (like Cerium(III) Sulfate) must be handled on a case by case basis as to the reasons for that. Pictured below is a graph of the solubility curves of several solid ionic substances. //Temperature towards gases:// All gases display a tendency opposite of what was said above as a general statement for solids, with respect to their solubility in water versus temperature. Gas solubility in water decreases with increasing temperature. This is largely due to the properties of gases with increasing temperature; properties we should all know by this point in time so it is no point saying them. This reason is one of the many of why soda is stored in the fridge, along with the fact that a warm soda simply isn't as satisfying. Pictured below is the solubility curve of oxygen, and all gases demonstrate curves similar to this.
 * //Temperature//**

They are the same as my previous wikis, and this might be the last time I actually put these down, instead just linking to past wikis for my settings before. But here you are, as protocol dictates... Informational: The Book (Chemistry: The Central Science) and Wikipedia Pictorial: Click on link for original source. A personal pic of the Brook may be added, in which case it would be from my personal stock. Otherwise picture sources are listed right below the pictures. http://www.sciencebyjones.com/solubility.htm
 * //Sources//**

As power, wisdom, and influence grows, so does the perilous cancer of paranoia. As my legacy continues to grow in these respects I have seen the same effects, and thus I must take care not to destroy myself while at the same time not allowing anyone else to do the deed either. But, for those of you people seeking my demise and ultimate destruction, I warn you now, he who wishes to slay the beast must go for the kill, for that which does not destroy it only makes it stronger. -AA You know what you can't destroy? The outdoor study area. It has god-like powers. And a raccoon with rabies lives there. -Nandish I miss having three recess breaks... I think there should be a recess break in High School too. :) -Slow Talker
 * //Last Words//**