Solutes and solubility Investigation One

What affects the solubility of a solute? Focus questions What affects the solubility of a solute? Is there a relationship between the concentration of a solution and the saturation point of a solute?

Vocabulary Solution-a mixture of two or more substances, that is the same throughout the mixture, usually a solid and a liquid. Solute-The substance that changes its state when a solution is created or that is present in the smallest amount. (usually a solid) Solvent-the substance in a solution that does not change its state when a solution is created or that is present in the largest amount.(usually a liquid)

More vocabulary dissolve- to completely mix with and become part of another substance. Soluble: the ability to be dissolved in another substance Concentration-The amount of one substance in a specific volume of another substance: it is usually described as grams per milliliter. Solubility-The property of mixing and dissolving in another substance.

And more vocabulary… Suspension-a mixture in which particles can be seen and easily separated by settling or filtration. Rate-How fast something occurs per unit of time. An example is speed which is distance in meters traveled per minute. Saturation point-a concentration above which the solute will no longer dissolve in the solvent.

Ionic solids in water The positive and negative ions are attracted to polar water molecules. Water molecules surround each ion as it leaves the surface of the crystal. Eventually all the ions go into the solution. See p.82

Molecular Solids in Water With sugar, which is not an ionic solid, the water breaks apart the individual molecules but does not break the covalent bonds. These molecules then become surrounded by water.

Examples of Concentration of cherry soft drink 50g of the powder 100 ml of water This means that 50 g of the powder is dissolved in 100 ml of water 100g of the powder This means that 100 g of powder is dissolved in 100 ml of water.

Concentration The second solution would have a concentration that is twice the concentration of the first solution because twice as much powder was added. The solution would be a darker red and have a much stronger cherry flavor.

Solubility The solute is completely dissolved when every solute particle is surrounded by many solvent particles:

Changing Solubility Solubility in a solution will change when conditions change, such as: Temperature-Solids dissolve better at increased temperatures, for example: fudge or candy. Gases dissolve better in cooler solutes, for example: soda Type of solvent-”Like dissolves like” Ionic and polar compounds dissolve in polar solvents. Non polar compounds do not dissolve in polar solvents. Example: water-based paint can be cleaned up with just soap and water. Oil-based paints may require cleanup with turpentine.

Solutions