1. Cut out the table and glue it onto page 48.
Warm-Up 4/14/14
Cut out the table and glue it onto page 48.

2. Balancing Equations
Monday 4/14/14

4. Conservation of Mass
Chemical equations must follow the “Law of Conservation of Mass”= mass can neither be created nor destroyed in an ordinary chemical or physical process.
What you start with must show up in the end; atoms are just rearranged.

5. Good 2 slices of bread + peanut butter + jelly → PBJ
4 legs + seat → a chair
1C + O2 → 1 CO2

6. What is wrong with these?
lettuce + tomato + cheese → pizza
Mg + Cl2 → NaCl
2Mg + Cl2 → MgCl2

7. Balancing Equations
In order to follow the Law of Conservation, we need to make “Balanced Equations”
each side of the chemical equation has the same number of each type of element.

8. Do’s and Don’ts
DO balance equations by adding coefficients in front of reactants and products.
You DO NOT change subscripts!!

9. Final Balanced Equation
Examples
Given Equation
Starting Reactants
Starting Products
Final Reactants
Final Products
Final Balanced Equation
H2 + O2 → H2O
Na + O2 → Na2O

10. When Done: Analysis (pg.48)
What does the arrow mean?
What side of the equation are the reactants found? Products?
The Law of Conservation says the matter cannot be created or destroyed. How does this relate to balancing equations?
Why can’t you change the subscripts?

11. Basic Procedure
Write down the equation, count the # of each type of element on both sides of the arrow.
Place coefficients in front of the chemical cards to multiply the # of each element until they are the SAME on both sides.
Record the final counts of both reactants and products, then record what the final equation looks like!