1. What is a Chemical Reaction?

2. There are two types of changes to matter
Physical Change
Chemical Change
What’s the difference?

3. Physical Change
A change to a substance’s form or appearance, but does not change into a new substance
Examples: changes of state, cutting or bending, dissolving one substance into another, mixing substances together

4. So, what is a chemical reaction?
A change that involve the breaking & reforming of bonds to create new substances.
The result: a brand new substance is formed

5. Example #1
H2 + O2  H2O (water)
Bonds break
New bonds are formed

6. Example #2: Hydrochloric Acid
Reactants: hydrogen gas (H2) + chlorine gas (Cl2)
The bonds break
Atoms rearrange
Atoms form new bonds with each other.
Product (New substance): Hydrogen chloride (HCl)

7. Parts of a Chemical Reaction
In cooking, ingredients are combined to make food.
In chemical reactions, reactants are combined to make products.
The reactants are substances that are combined & changed in the reaction.
The products are the new substances that result from the reaction.

8. A chemical reaction rearranges the atoms of the reactants to form new compounds of the products.
No new atoms are created