Mixtures and Solutions

A mixture is a combination of two or more components that are NOT chemically combined, and retain their identities. Mixtures can be physically separated. The identities of the substances DO NOT change. A homogeneous mixture is also called a solution.

Mixtures When a mixture’s components are easily recognizable, such as pizza, it is called a heterogeneous mixture. In a homogeneous mixture such as chocolate milk, the component particles cannot be distinguished, even though they still retain their original properties.

Mixtures Common Techniques for Separating Mixtures Distillation – separates a mixture based on boiling points of the component. Examples : saltwater crude oil into gasoline and kerosene Magnet – separates iron from other objects. Centrifuge – spins and separates according to densities.

Solutions A mixture that appears to be a single substance but is composed of particles of two or more substances that are distributed evenly amongst each other. A solution may be liquid, gaseous, or solid. Examples of solutions Liquid - seawater Gas - air Solid - alloys

Solutions Dissolving – The process in which particles of substances separate and spread evenly amongst each other. Solute – substance that is dissolved. A solute is soluble, or able to dissolve. A substance that is insoluble is unable to dissolve, forms a mixture that is not homogeneous, and therefore NOT a solution. Solvent – substance in which solute is dissolved.

Solubility The solubility of a solute is the amount of solute needed to make a saturated solution using a given amount of solvent at a certain temperature. Solubility is usually expressed in grams of solute per 100 ml of solvent (g/100ml) Three (3) methods that affect solubility –Mixing, stirring, or shaking –Heating –Crushing or grinding