4 Types of Chemical Reactions
6th Grade Science
Physical Changes and Chemical Reactions:
Physical Change
Physical changes are about energy and 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.
Physical or Chemical?
Crushing a canMelting an Ice
Cube
Physical or Chemical?
A Rusty NailThe Statue of
Liberty
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.
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.
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.
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.
