Unit 4 Lesson 3

Physical Vs. Chemical Change

Physical Change - change in matter in which a substance changes form but not identity. These can also include color or temp.

• Ex: H2O(l) ---> H2O(s)

Chemical Change - change in matter resulting in the formation of a new substance or substances with new properties.

• Ex: 2Na(s) + Cl2(g) ---> 2NaCl(s)

You're not always able to see if a physical change is accompanied by a chemical change simply through observation. You need a chemical equation.

Dissolving of a substance can either be physical or chemical but is considered physical.

Practice Problems
1) physical change is not a change in identity of the substance while a chemical change is a change in identity by rearranging the atoms.
6) a. Chemical because the product is not identical to the reactants b. Physical because only the phase of the substance changes

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