8th Grade Physical Science Presented by Betsy Sanford Mixtures on My Mind 8th Grade Physical Science Presented by Betsy Sanford

Classification and Matter to sort by characteristics, traits, properties, etc. used for identification, for study, for learning, for uses of matter Types of Matter elements (pure substances) mixture (combinations of substances made by physical changes) compound (pure substances, combinations of substances made by chemical changes)

Properties of Mixtures May be solid alloys like jewelry metals May be liquid like tea and lemonade May be gas like air May be any combination of pure substances or compounds The individual substances are combined without changing themselves

Types of Mixtures Solution substances dissolved in other substances solute + solvent = solution the ability to dissolve is called solubility water is the universal solvent ex. - Kool-Aid diluted = more solvent, more water concentrated = more solute

Types of Mixtures Suspension Colloid particles may spread throughout the mixture, but will settle particles scatter or block light, large enough to see ex. - snow globe, oil and vinegar salad dressing, trail mix Colloid particles will not settle particles will scatter light are not large enough to see ex. - dairy products, Jell-O

Classes of Mixtures Homogeneous Heterogeneous looks the same throughout cannot see individual parts ex. milk, tea (colloids, solutions) Heterogeneous larger parts can be seen different parts can be seen ex. Snow globe (suspensions)

Ways to Separate Mixtures Mixtures may be separated fairly easily even hand-picked apart Evaporation liquid to gas leaves solids behind such as evaporating water from salt water solutions which allows salt to form crystals Distillation boiling to separate liquids all liquids have different boiling points collect vapors of each substance

Ways to Separate Mixtures (cont.) Centrifuge separates substances based on density the more dense substance will be pulled to the side of the spinning container because of gravity Magnetism metals will separate from non-metals Filtration smaller particles will pass through filters while larger particles stay behind

Examples Chart Gas in Gas Air (nitrogen, oxygen, etc.) Gas in Liquid Soda Liquid in Liquid Oil and vinegar salad dressing Solid in Liquid Sugar in Kool-Aid, salt water Solid in solid Trail mix, salad, concrete, alloys

Summary Application Which diagram represents a mixture? Why? What are the other two? Why do we call the other two “pure substances”?