What is Solubility?
Salt dissolving in Water

The solubility of a substance is the amount of that substance needed to form a saturated solution, with a solvent. What this pretty much means is that their is a specific amount of that substance that will dissolve in a particular amount of solvent. For example the solubility of salt in water is thirty-seven grams of salt per one-hundred grams of water at room temperature. Not all substances have the same solubility they are all very distinct. Solubility is affected by many factors, like pressure, temperature, and the kind of solvent.

What is a Solvent?
Solvent is in Cup

A solvent is a chemical compound that is used for dissolving other compounds. Solvents are usually liquids, but gases and solids can also serve as solvents. One of the most important solvents would be water. Water is a very important solvent because it can dissolve many inorganic compounds and some organic compounds. For a liquid to be a good solvent it has to have a couple of characteristics. Some characteristics would be that the solvent is able to dissolve another substance without reacting to it and for the solvent to have a fair volatile. Volatile is when the substance can evaporate easily, even at normal temperatures.

What is the Universal Solvent?
Water is known as the universal solvent, because water can dissolve a large v
Universal Solvent: Water
ariety of substances. That’s the reason it is such a good solvent, it can dissolve more substances than any other liquid. The fact that water picks up valuable chemicals like minerals and nutrients when it goes through the air, the ground, or even through our bodies, is very important to everything living on Earth. Water is also a very good solvent because it has the two characteristics I mentioned earlier. It can dissolve another substance without reacting to it and it has a fair volatile.

How does pressure affect the solubility of a substance?
Pressure affect Solubility

Pressure doesn’t have a great affect on the solubility of solids and liquids, but on the other hand it has a very enormous affect on the solubility of gases. A gas’s “willingness” to dissolve(become a liquid) becomes greater with the pressure of that gas above the solution. When you double the pressure the solubility is doubled also. An example of this taking action would be, why the cap of a soda cap must be screwed on tight. When the cap is screwed on tight it keeps the gas from escaping the bottle, this keeps a high pressure and so it keeps more “bubbles” dissolved in the water. When you open the bottle the pressure gets smaller, and the solubility also decreases.

How does temperature affect the solubility of a substance?
Solubility can be affected by temperature in a very drastic way. When you are trying to dissolve a solid into a liquid, heat usually will be the best to increase the solubility. For example salt or sugar dissolves best in hot water rather than in cold. This happens because when you dissolve a solid into a liquid form it involves breaking down the stiff form, or crystal lattice of the solid. Although heat is usually the best in these cases, there are some exceptions. For example, sodium sulfate, this solid becomes less soluble in increasing temperatures. Dissolving a gas in a liquid usually creates heat. As a result, most(not all), gases become more soluble with declining temperatures rather then rising temperatures. This happens because gas molecules have to “slow down” or loose kinetic energy, to turn into a liquid. When the temperatures rise the dissolved gases get the energy to break free.


Why Do Some Solids Dissolve in Water?

Some dissolve because they contain ionic compounds an example is (salt) within it the positive and negative ions are held together by the strong force of attraction. If the solid dissolves in water the ions would have released into solution. Just like the sugar you use to sweeten coffee or tea is a molecular solid, in which the individual molecules are held together by relatively weak forces. When sugar dissolves in water, the weak bonds between the individual sucrose molecules are broken, and these molecules are released into solution.


Some examples of insoluble substances

Insoluble substances means that their solute, some examples are pencils, tires, pins, clothes hanger, paper clip, beaker, fleaker, conical flask, graduated cylinder, volumetric flask, computers, books, plastic bags, coins, gold, wood, desks, boats, paper, cards, cars, minerals, soil, and CD/ DVD’s there are millions of insoluble substances but these are a few. Which the term insoluble basically means that their poorly or very poorly compounds.


How does the solvent affect the solubility of a substance.There are great solvents but substances that dissolve in water are know as polar or charged ionic compounds made of negative and positive charged atoms. For example Polar water attracts polar molecules and ions and pushes out non-polar and non-charged substances.


Examples of soluble substances

Water's polar nature also helps water dissolve many polar molecules. For example, water easily dissolves ethyl alcohol. Examples are salt, sugar, Kool Aid powder, shampoo, Potassium Chloride, Potassium Iodide, and Sodium Nitrate. The solubility of a substance fundamentally depends on the used solvent as well as on temperature and pressure.


The rate of dissolving is very important property of solutions.The rate of dissolving depends on several factors, Temperature, Agitation, and Particle size. For most solids solutes, the rate of dissolving is greater higher temperatures. At high temperatures, the solvent molecules have greater kinetic energy and collide with undissolved solid molecules more frequently.



Research Citations:
Roper, Gerald C. "Solubility. " Grolier Multimedia Encyclopedia. Grolier Online, 2012. Web. 25 Jan. 2012.

"The Universal Solvent." Water. Expert Space, 2012. Web. 25 Jan. 2012.

"Water: The Universal Solvent." The New Book of Popular Science. Grolier Online, 2012. Web. 25 Jan. 2012.

Zieger, Herman E. "Solvent. " Grolier Multimedia Encyclopedia. Grolier Online, 2012. Web. 25 Jan. 2012.

Movie/ Image Citations:
Solubility. Prod. Brian Jerome. Brian Jerome, 1998. Discovery Education. Web. 30 January 2012. <http://www.discoveryeducation.com/>.