Classification and Matter

Types of Matter Pure substances Elements (PT) Compounds (ionic, covalent, metallic) Mixtures (combinations of substances made by physical changes)

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 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

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

looks the same throughout cannot see individual parts Classes of Mixtures Homogeneous 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. trail mix (suspensions)

particles may spread throughout the mixture, but will settle Types of Mixtures Suspension 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

substances dissolved in other substances solute + solvent = solution 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

Electrolytes Electrolyte – a substance that dissolves in water to give a solution that conducts electric current. Nonelectrolyte – a substance that dissolves in water to give a solution that does not conduct an electric current.

Factors That Affect Solubility Surface area – because the dissolving process happens at the surface area of a solute, crushing or grinding the solute speeds up the rate of dissolution. Agitation – stirring or shaking helps spread out the solute particles which increases the rate of dissolution. Heating – speeds up the particle motion therefore helping it dissolve the solute. Pressure – changes how gases dissolve in liquids.

Saturation Saturated solution – a solution that contains the maximum amount of dissolved solute. Supersaturated solution – a solution that contains more dissolved solute than a saturated solution, eventually excess solute will precipitate out. Unsaturated solution – a solution that does not have the maximum amount of dissolved solute.

Solubility curve Saturated Supersaturated Unsaturated

Solubility curve Any solution can be made saturated, unsaturated, or supersaturated by changing the temperature.