WATER AS A SOLVENT
•The polar nature of the water molecule enables water to dissolve a large number of substances.
1.Sodium chloride in sea water.
2. Sugar in coffee.
3. Alcohol in beer.
4.Carbon dioxide in fizzy drinks.
Solutions have the following important characteristics:
•They are homogeneous (solute (substance being dissolved) and solvent (liquid solute is dissolved in) cannot be distinguished from each other).
•The dissolved particles are too small to see.
•The proportion of dissolved solute varies from one solution to another.
•A solution is an evenly distributed mixture of atoms, molecules, or ions.
•When a solid, liquid or gas dissolves in water, an aqueous solution is formed.
•The dissolved solid, liquid or gas is the solute.
•The water is the solvent.
•The process of dissolving is called dissolution.
•When the two substances are liquids, they are said to be miscible.
FORCES INVOLVED IN DISSOLVING
For a substance to dissolve, the interactions between solvent-solvent and solute- solute must change. If dissolving is to occur the solute-solvent interactions need to be strong.
LIKE DISSOLVES LIKE RULE
This predicts whether a substance is likely to dissolve in another substance.
•Polar solutes will dissolve in polar solvents
•Non-polar solutes will dissolve in non-polar solvents.
Solutions image courtesy of By Maxim Bilovitskiy (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)], via Wikimedia Commons