Matter Part 2

There are two types of mixtures: homogeneous and heterogeneous. The only similarities between the two, are that both are mixtures of two or more components. There are several differences.

Homogeneous Mixtures

are composed of two or more components that are: equally (uniformly) distributed throughout the system, miscible (will dissolve), of a single phase, easily dispersed through a membrane, and inseparable by mechanical means. Chemical solutions are examples*:

Salt dissolved in water, Soapy water, Hydrochloric acid & water, Alcohol & water, Sugar dissolved in water, Ammonia water, Phenolphthalein dissolved in alcohol and water, Extracts of coffee beans, Extracts of tea leaves

* Colloids are sometimes referred to, at the macro level, as homogeneous, but at nanometer or microscopic levels, even these are heterogeneous, many having very small but varying particle sizes from 1 - 1000 nanometers, so in this state, they can never be part of a truly homogeneous mixture such as a solution.

Heterogeneous Mixtures

are composed of two or more components that are: unequally (not uniformly) distributed though out the system, immiscible (won't dissolve), may be of different phase, unable to disperse through most membranes, and separable by mechanical means. There are probably more possibilities for this type of mixture than the first. Some examples are:

Sand & water (liquid & solid), Carbonated beverage like soda or beer (gas & liquid), Orange juice with pulp in it (liquid & solid), Water with ice cubes in it (liquid & solid), Chicken noodle soup (liquid & solid), Oil & water (immiscible liquids), Salad (solids & solids), Trail mix (solids & solids), Granite (solids in a solid), Table salt crystals & sugar crystals (solids & solids), Table salt crystals & iron filings (solids & solids), Colloids

MixturesA mixture is a combination of substances which are not chemically joined together.Mixtures have the same properties as their componentsThere is no fixed proportion between the componentsThe components can be separated from the mixtureExamplessugar and saltair with nitrogen, oxygenSolutionsA solution is a mixture in which other substances (solutes) are dissolved.The components in a solution may not be separated from the solution by leaving it to stand, or by filtrationIf a material dissolves in a liquid the material is said to be soluble. A solution is saturated if no more solute can be dissolved with temperature remaining constant. Examplessalt in sea waterSuspensionsA suspension is a mixture of liquids with particles of a solid which may not dissolve in the liquid.The solid may be separated from the liquid by leaving it to stand, or by filtrationExamplessand in water

Compounds

A compound is a substance formed when two or more elements are chemically joined. Water, salt, and sugar are examples of compounds. When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of. A chemical formula is used a quick way to show the composition of compounds. Letters, numbers, and symbols are used to represent elements and the number of elements in each compound.

ElementsElements are substances that cannot be separated into simpler substances. Salt is made up of the elements sodium and chloride. Water is made up of the elements hydrogen and oxygen.