Physical vs. Chemical Properties Unit 2.5

Introductory Video

Physical Properties Physical Property- characteristic of a substance that you can observe without changing the identity of the substance Examples: color, density, melting point, and boiling point. Physical Change-a change of matter from one form to another without changing what it’s made of Examples: Water freezing (solid), then melting (liquid), then evaporating (gas)

Physical Properties Distillation- separating a mixture physically through evaporating a liquid and re-condensing its vapor. Ex. Wine Distillery

Chemical Properties Chemical Property- characteristic of a substance that indicates whether it can undergo a certain chemical (permanent) change Chemical Change- changes the types and amounts of elements in the substance Indications that a chemical change MAY have occurred: Change in Smell Produces heat, light, or sound Color change (does not always indicate a chemical change though…ex. Example: blue and yellow gatorade make green gatorade- just a mixture) production of gas or precipitate (solid) Dark bottles- blocks UV light- prevents change in identity of the liquid in the bottle (wine)

Physical vs.Chemical Changes Physical or Chemical Change? Baking a Cake Boiling Water Scrambling an Egg

Physical and Chemical Changes Weathering: 2 Types Physical change: An example is when rocks split as water freezes or as erosion occurs Chemical change: An example is when oxygen in the air reacts with iron in the rock to make iron oxide (rust) Ex. Physical Weathering Ex. Chemical Weathering

Law of Conservation of Mass Mass cannot be created or destroyed, it can only change forms Burning a log seems to make mass disappear “missing” mass is actually present in the gases and the heat energy that are produced as the log burns