1. Describing Chemical Reactions

2. Learning Scale
4 – Investigate and describe the compounds formed by bonding elements. 3 – Describe why certain elements bond with others. 2 – Use the periodic table to identify the number of protons, neutrons, or electrons in an element. 1 – Identify patterns on the periodic table.

3. Classifying Chemical Reactions
Synthesis – two or more elements combine to make a more complex substance.
Decomposition – Compounds are broken into simpler products.
Replacement – When one element replaces another in a compound

4. What type of reaction?

5. What type of reaction?

6. What type of reaction?

7. What type of reaction?

8. What type of reaction?

9. What are Chemical Equations?
A chemical equation is a short, easy way to show a chemical reaction using symbols instead of words.
A reactant is the substance you have at the beginning of the reaction (left of arrow).
A product is the new substance that formed during the reaction (right of arrow)

11. Balancing Chemical Equations
Write the equation.
H2 + O H2O
Count the atoms.
H2 + O H2O

12. Use Coefficients to Balance the Atoms.
2 H2 +__ O H2O
Look Back and Check
The left and right sides of the equation should be equal.

13. Law of Conservation of Mass
The principle of conservation of mass states that in a chemical reaction, the total mass of the reactants must equal the total mass of the products.

14. Learning Scale
4 – Investigate and describe the compounds formed by bonding elements. 3 – Describe why certain elements bond with others. 2 – Use the periodic table to identify the number of protons, neutrons, or electrons in an element. 1 – Identify patterns on the periodic table.