Mixtures and Solutions

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

Suspension A mixture in which particles of a material are dispersed through- out a liquid or gas but are large enough that they settle out. Particles are insoluble, so they DO NOT dissolve in the liquid or gas. Particles can be separated using a filter. Examples: Salad dressing Medicines that say “shake well before use”

Colloids A mixture in which the particles are dispersed throughout but are not heavy enough to settle out. Made up of solids, liquids and gases. Examples : Mayonnaise Stick deodorant milk

Heterogeneous and homogeneous refer to mixtures of materials in chemistry. The difference between heterogeneous and homogeneous mixtures is the degree at which the materials are mixed together.

A homogeneous mixture is a mixture where the components that make up the mixture are uniformly distributed throughout the mixture. Homogeneous mixtures: air, blood, saturated sugar water

A heterogeneous mixture is a mixture where the components of the mixture are not uniform or have localized regions with different properties. Heterogeneous mixtures: rocks, oil and water, soup, pizza