Physical and ChemicalChanges

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?

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