Classification of Matter

A substance that has constant composition & properties Terms Definition Example Pure Substance A substance that has constant composition & properties (contains only one kind of particle) Elements A pure substance that cannot be broken down by ordinary means. Any example from the periodic table. All diatomic molecules (exists in those forms naturally). Compounds A pure substance that contains two or more different elements in a fixed proportion. Elements are chemically bonded. CO2, H2O Not O2/H2/N2

Molecules The combination of two or more atoms. From elements: diatomic From compounds: e.g. CO2 Mixture A substance that contains two or more different pure substances or types of particles that are not chemically combined. Components can be separated by physical means (e.g. filtration, evaporation, distillation etc.) (variable composition & properties) Homogeneous Solution A mixture that has “uniform” composition - One phase. The components within the solution are not identifiable with the eye. Sugar & water, air Perfume =alcohol +fragrance All alloys

Solute The particle in smaller proportion. The dissolved particle. Sugar in water Solvent The particle in larger proportion. The substance in which the solute is dissolved in. Often water: universal solvent Alloy Homogeneous mixture of one or more METALS. Steel = iron + carbon Bronze = copper + tin + zinc Brass = copper + zinc Sterling silver = Ag + Cu Stainless steel = Fe + Cr + Ni

Ordinary Mechanical Mixture Heterogeneous Mechanical Mixture A substance in which the different components are identifiable. Two or more phases. Ordinary Mechanical Mixture Cross this one out.

Suspension Suspended particles can be seen with the unaided eye. If left undisturbed, gravity will cause the particles to separate. Oil & water, sand & water, oil & vinegar Fresh milk (not homogenized)

Colloid Suspended particles cannot be seen with the unaided eye. Gravity will not cause them to separate. (they appear to be homogeneous) Gelatin = solid + liquids Whipped cream = gas + liquid Mayonnaise = egg + oil + vinegar (water, sugar, salt etc.) paints, glues, butter, milk

Emulsion A suspension of liquids where separation of particles are prevented through the use of an emulsifying agent. Fresh milk suspends naturally, needs to be emulsified using homogenizationMilk is an emulsified colloid or emulsion.

Tyndall Effect The scattering of a beam of light caused by particles in a colloid. Allows solutions and colloids to be distinguished. (particles in colloid are larger than particles in solutions)

Homefun Workbook: pg. 20-21 Read Textbook: “Developing the Atomic Theory” pgs. 168-175 Textbook Answer: pg. 175 #2-5