What is a solution?
SOLUTIONS are homogeneous mixtures (i.e. the same composition throughout the mixture) that consist of something dissolved (the SOLUTE) into a substance doing the dissolving (the SOLVENT).
Factors that affect solubility
Some substances simply do not dissolve, or at least very much. These substances are said to be insoluble. Other substances dissolve to varying degrees, and can be designated as slightly soluble, soluble or very soluble. The solubility of solid substances is affected directly by the temperature of the solution. That is, as the temperature of the solution increases, the amount of the solute that can be dissolved also increases.
The RATE of dissolving is also affected by various actions.
- stirring
- pulverizing
- heating
Surface tension and the good old hydrogen bond
Water is highly unusual. It definitely does not fit what it "should" do as would be predicted by other members in the oxygen group on the Periodic Table.Just remember, most of the anomalies (i.e. weird, but explainable observations) of water are explained by the polar nature of the molecule and the hydrogen bonding that occurs.
Watch a Bill Nye video about surface tension by clicking here. This video will open in a new window. To return to this page, just close the video window.
Solubility Curves
We can describe the quantitative nature of solutions by using graphs called solubility curves. These graphs can be useful in making solutions of various types. In fact, solutions can be divided into three main categories based on the relative amount of solute in the solution at various temperatures.- Unsaturated - able to dissolve more solute
- Saturated - right at the limit of dissolved solute at that temperature
- Supersaturated - "over the limit" of a saturated solution (accomplished by heating, then cooling)
Check out this next video to see supersaturation in action.
