Physical and Chemical Changes

Physical Changes Physical changes- A change that affects one or more physical properties of a substance but does not change the chemical identity of the substance. If you melt a block of ice, you still have H2O at the end of the change. 

Physical Changes Any change in size, shape, form, or state where the identity of the matter stays the same Example: cutting a watermelon into slices tearing up a sheet of paper sharpening a pencil Often easy to reverse with: filtration, magnetism, evaporation, distillation and centrifuge (spinning)

Physical Change Signs that a physical change is taking place Change in Appearance Change in state of matter Observed without doing anything Measured quantity Key words to look for Melts Evaporates Bent Conductor

Physical Changes Some common examples of physical changes are: melting, freezing, condensing, breaking, crushing, cutting, and bending.

Chemical Changes Chemical changes, or chemical reactions, are changes that result in the production of another substance. 

Chemical Changes Signs that a chemical change (reaction) is taking place Bubbles form Odor released/ forms Fizzing occurs Something burns A gas is released Heat produced Light produced Precipitate (solid) forms Rusting occurs A color change occurs Key words to look for Burning Reacts Bubbles Tarnishes Explodes Heats up Sours

Physical or Chemical Change? Painting Wood PHYSICAL

Physical or Chemical Change? Burning Paper CHEMICAL

Physical or Chemical Change? Digestion of food CHEMICAL

Sugar dissolving in water PHYSICAL Physical or Chemical Change? Sugar dissolving in water PHYSICAL

Iron turning red when heated PHYSICAL Physical or Chemical Change? Iron turning red when heated PHYSICAL

Physical or Chemical Change? Evaporation PHYSICAL

A pond freezing in winter PHYSICAL Physical or Chemical Change? A pond freezing in winter PHYSICAL

Physical or Chemical Change? Melting ice PHYSICAL

Physical or Chemical Change? Cutting wire PHYSICAL

Physical or Chemical Change? Painting fingernails PHYSICAL

Physical or Chemical Change? Cutting fabric PHYSICAL

Physical or Chemical Change? Baking muffins CHEMICAL

Physical or Chemical Change? Shattering glass PHYSICAL

Decomposition of old leaves CHEMICAL Physical or Chemical Change? Decomposition of old leaves CHEMICAL

Physical or Chemical Change? Wrinkling a shirt PHYSICAL

Physical or Chemical Change? An old nail rusting CHEMICAL