1. 4 Types of Chemical Reactions 6 th Grade Science

2. Physical Changes and Chemical Reactions: Physical Change  Physical changes are about energy and states of matter.states of matter.  Melting an Ice-Cube Chemical Reaction  Chemical changes happen on a molecular level when you have two or more molecules that interact and create a new molecule or two.

3. Physical or Chemical? Crushing a canMelting an Ice Cube

4. Physical or Chemical? A Rusty NailThe Statue of Liberty

5. 4 types of Chemical Reactions 1. Synthesis Reaction A + B  AB  Reactants A and B combine chemically to form a more complex molecule, AB. AB then stores energy in its bonds.

6. 4 Types of Chemical Reactions 2. Decomposition Reactions AB  A + B  The molecules AB is chemically broken down to smaller molecules, and in doing so, energy is released.

7. 4 Types of Chemical Reactions 3. Exchange Reactions AB + CD  AD + CB  These reactions involve both synthesis and decomposition reactions. The reactants exchange parts to yield new chemical compounds.

8. 4 Types of Chemical Reactions 4. Reversible Reactions A + B  AB  Chemical bonds can be made and they can be broken depending on the requirements of the body.  Example: Glycogen molecules can be synthesized from glucose molecules for storage in liver cells, and glycogen can be decomposed to glucose by the liver during periods of low blood sugar.