Physical and Chemical Changes Objective 4 TEKS 8A Marivel Macias

Chemical Change The elements and/or compounds at the start of the reaction are rearranged into new product(s) (i.e. compounds or elements).

Oxidation of Iron - a chemical change: For example iron has the potential to rust given the right conditions. This is a chemical property. If iron does rust, this is a slow chemical change since rust is an iron oxide with different properties than iron metal. Iron + oxygen + water  Iron rust.

Physical Change A physical change takes place without any changes in molecular composition. The same element or compound is present before, during and after the change.

Changes in States - a physical change: The three states of matter are: solid, liquid, and gas.

Digestion : Physical or Chemical Change? Identify the following: –Biting an apple –Chewing –Swallowing –Break down of carbohydrates in stomach, small intestine and large intestine.

Rock Cycle: Physical or Chemical Changes?

Physical or Chemical Change?

Phase Change –From liquid water to gas vapor Boiling Point –100 degrees Celsius at 1 atm

Physical or Chemical Change? Dry Ice Sublimation carbon dioxide (s)  carbon dioxide (g)

Physical or Chemical Change? Plus Heat Energy

Physical or Chemical Change? Iodine + Zinc  Zinc Iodide