1. Warm Up:
Partner sitting closest to the door silently write down what happens during a synthesis reaction.
Partner sitting closest to the window silently write down what happens during a decomposition reaction.
Now: explain them to each other, compare/contrast the reactions door partner go first

2. Balancing Equations

3. Q: How could you chemically describe this reaction?
Look at this rusty bike wheel. It has been left outside in damp weather too many times, so the iron in the metal parts has rusted. Iron rusts when it combines with oxygen in the air. Iron rusting is an example of a chemical reaction. In a chemical reaction, substances change into entirely different substances. For example, the iron in the bike and the oxygen in the air have changed into rust.

4. Q: How could you chemically describe this reaction without using words
Q: How could you chemically describe this reaction without using words? Scientists use an equation.
Look at this rusty bike wheel. It has been left outside in damp weather too many times, so the iron in the metal parts has rusted. Iron rusts when it combines with oxygen in the air. Iron rusting is an example of a chemical reaction. In a chemical reaction, substances change into entirely different substances. For example, the iron in the bike and the oxygen in the air have changed into rust.

5. A: Chemical equations are used to represent: chemical reactions

6. What is the general equation for the reaction in which iron rusts?
Fe + O2 → Fe2O3
Look at this rusty bike wheel. It has been left outside in damp weather too many times, so the iron in the metal parts has rusted. Iron rusts when it combines with oxygen in the air. Iron rusting is an example of a chemical reaction. In a chemical reaction, substances change into entirely different substances. For example, the iron in the bike and the oxygen in the air have changed into rust.
Iron + Oxygen → Iron Oxide (RUST)
What type of bond forms in the product? Ionic (metal+nonmetal)

7. What type of chemical reaction is this? How do you know that?
Fe + O2 → Fe2O3
Look at this rusty bike wheel. It has been left outside in damp weather too many times, so the iron in the metal parts has rusted. Iron rusts when it combines with oxygen in the air. Iron rusting is an example of a chemical reaction. In a chemical reaction, substances change into entirely different substances. For example, the iron in the bike and the oxygen in the air have changed into rust.
Synthesis: Two separate elements chemically join to form one new compound

8. What are the reactants and products?
Fe + O2 → Fe2O3
Reactants
Products
The atoms/compounds you have BEFORE the reaction occurs.
The atoms/compounds you have AFTER the reaction occurs.

9. 2Al(s) + 3I2(s)  Al2I6(s) VIDEO: Aluminum and Iodine Reaction
Watch the video and tell me how you know that this is a chemical change, and what type of bond forms in the product:
2Al(s) + 3I2(s)  Al2I6(s)
VIDEO: Aluminum and Iodine Reaction

10. When is an equation balanced?
When there is the same the number of each type of atom on both sides
BEFORE:
4 White (H)
1 Black (C)
4 Red (O)
AFTER:
4 White (H)
1 Black (C)
4 Red (O)

11. Chemical Equations
coefficients
4 Al (s) O2 (g)  2 Al2O3 (s)
Coefficients are: numbers in front of the letters, represents how many molecules you have

12. Chemical Equations 4 Al (s) + 3 O2 (g)  2 Al2O3 (s)
subscripts
Subscripts are: numbers behind the letters, represent how many atoms are in that molecule

13. Chemical Equations 4 Al (s) + 3 O2 (g)  2 Al2O3 (s)
The letters (s) solid, (g) gas, and (l)liquid are the physical states, (aq) means aqueous
The arrow means : yield/create/produce/form

14. Learning Check
2Li (s) + 2H2O (l)  2LiOH (aq) + H2 (g) What does “2“ mean in front of LiOH?
Number of molecules
What does “2“ to the right of “H2” mean?
Number of atoms of H
What does “(aq)“ to the right of LiOH mean?
Aqueous solution
What does ““ mean?
Yield, form, produce

15. Q: What is the chemical equation for this reaction?
A: The chemical equation is:
C + O 2 → CO 2

16. Q: How have the atoms of the reactants been rearranged in the products of the reaction?
C + O 2 → CO 2
A: Carbon atom chemically bonds with
two oxygen atoms.

17. What bonds are broken and what new bonds have formed?
C + O 2 → CO 2
C + O=O →
O=C=O
Bonds
Break
New Bonds Form
A: Bonds between the Oxygen atoms have broken New bonds have formed between Carbon and the 2 Oxygens

18. Q: What type of bond has formed between the Carbon and 2 Oxygens?
C + O 2 → CO 2
C + O=O →
O=C=O
Bonds
Break
New Bonds Form
Q: What type of bond has formed between the Carbon and 2 Oxygens?
A: COVALENT Bond (Nonmetal to nonmetal)

19. What type of chemical reaction is this and how do you know?
C + O 2 → CO 2
A: Synthesis: Two separate elements chemically join to form one new compound

20. Is this a balanced equation?
The charcoal used in a grill is basically carbon. The carbon reacts with oxygen to yield carbon dioxide. The chemical equation for this reaction,
C + O2  CO2, R P
Count the number of atoms of each element found in the reaction.
1 C
1 C
2 O
2 O
Is this a balanced equation?
YES

21. Yes, this is a chemical change, but what type of reaction is it
Yes, this is a chemical change, but what type of reaction is it? How do you know that?
C + O2  CO2,
Combustion: O2 present, give off heat, light, CO2,

22. Learning Check
Q: What needs to happen for a chemical reaction (change) to take place?
A: Bonds between atoms of the reactants
break and NEW bonds form to create
the products

23. Q: Is this chemical reaction correct? Explain why.
Learning Check
Q: Is this chemical reaction correct? Explain why. + 
A: No. The numbers of each type of square on both sides are not equal

24. Learning Check +  Why is this reaction correct?
The numbers of each type of atom on both sides are equal.
(so the atoms rearranged) + 
NEW PRODUCTS

25. For example: O2 is Oxygen but O3 is Ozone
Remember: To Balance an equation, you are only allowed to add Coefficients (the numbers in front of chemical formulas in the equation) You CANNOT add or change the subscripts because this would change the identity of the molecules
For example: O2 is Oxygen but O3 is Ozone
The order of the Coefficients in the Chemical Equation is important because this is how you write the COEFFICIENT RATIO.

26. Balancing using shapes
____H2 + ____O2  ____H2O 2 1 2
Is this reaction balanced? NO
BALANCED !
Now fix the H on the left.

27. Balancing Equations using T-chart
___ H2(g) + ___ O2(g)  ___ H2O(l)
1. Count the number of atoms of each element found in the reaction. R P
H - 2
H - 2
O - 2
O - 1
This equation is NOT balanced!

28. Balancing Equations using T-chart2 1
___ H2(g) + ___ O2(g) ---> ___ H2O(l) 2
R P
H H - 2
O O - 1
2. Add coefficients
to balance the atoms 4 4 2
3. Don’t forget to recount.
Now it is
balanced!
Now fix the H on the left.
Don’t forget there is a 1 in front of O2.

29. _____Fe + ____O2  ____Fe2O3
Now You Try!
Now fix the Fe atoms
2 x 2 = 4
_____Fe + ____O2  ____Fe2O3 4 3 2 6
Find the common denominator:
6/3 = 2
6/2 = 3
Coefficient ratio: 4:3:2

30. 2:3 – find a common multiple
Now You Try Again!
RULE: Balance O and H Last!
Al O2  Al2O3 2 3 2 R P 4 2
2 Al
2 x 2 = 4
1 Al
2 x 3 = 6
2 O
3 O
3 x 2 = 6
2:3 – find a common multiple
Coefficient ratio: 4:3:2

31. Meaningful Talk
Door partner: explain how to balance an equation without looking at your notes Window partner: look at your notes while they explain, let them know if they explained it correctly, correct them if they are wrong Questions?