1. Do Now – name and count the atoms
Carbon: 1
Oxygen: 2
2. 2NaAu(CN)2
Sodium: 2
Gold: 2
Carbon: 4
Nitrogen: 4
3. 3N(O2H2)2
Nitrogen: 3
Oxygen: 12
Hydrogen: 12
Example: BaBr2
Barium: 1
Bromine: 2

2. Homework and Announcements
USA TestPrep (due Mondays)
Finish independent practice problems (slide 23)
Summary
Test Averages – A List 

3. Title: Endo vs Exo
L.O. SWBAT determine if a reaction is endothermic or exothermic.

4. Chemical Bond Review – Polar vs Non Polar

5. REACTANTS  PRODUCTS Reactants: Will be changed into new substance.
What you start with.
Products:
New Substance formed
What you end up with.

6. Thermal Energy: “Movement of Heat”
FLOWS: warmer matter to cooler matter.
Chemical Reactions: Released or absorbed
Higher temperature = faster particles = more thermal energy

7. Which of the following has more thermal energy?
A melted chocolate bar.
A solid chocolate bar.
Why?
Higher temperature = higher thermal energy

9. Exothermic vs Endothermic

10. Heat is absorbed (heat is taken in) Heat is a reactant.
Endothermic change:
Endo - In Thermos - heat
Example:
Ice + Heat  Water (Physical change)
Ca + Cu + Heat  CaCu (Chemical change)
Heat is absorbed (heat is taken in)
Heat is a reactant.

11. Heat is absorbed so the particles move faster.
Which of these is endothermic?
Liquid water changes to Solid ice
Solid ice changes to Liquid water
Why?
Heat is absorbed so the particles move faster.

13. Heat is released (heat exits) Heat is a product.
Exothermic change:
Exo - Out Thermos - Heat
Example:
2Mg + O2  Heat + Light + 2MgO (Chemical change)
Water  Heat + Ice (Physical change)
Heat is released (heat exits)
Heat is a product.

14. Which of these is a exothermic change?
Instant cold packs
Instant hand warmer pack
Why?
Because the hand warmer is releasing heat.

16. Endothermic or Exothermic, Why?
Pair Share
Endothermic or Exothermic, Why?
1. Photosynthesis.
(CO2 + H2O + Energy  O2 + Glucose)
Endothermic. Energy is a reactant.
2. Fireworks exploding?
Exothermic.
Powder + O2  Heat + Light + Gas
3. Baking a cake?
Endothermic. Batter + Heat  Cake

17. “Elephant Toothpaste”
2H2O H2O + O2
Is this equation balanced?
releases heat or absorbs heat?
Is the heat a reactant or a product?
Endothermic or Exothermic?

18. Elephant Toothpaste

19. “Elephant Toothpaste”
2H2O H2O + O2
Is this equation balanced?
releases heat or absorbs heat?
Is the heat a reactant or a product?
Endothermic or Exothermic?

20. Fire with Science Bob

21. NO YES Problem 1 Problem 2 2NaClO3  2NaCl + 3O2 + heat
C3H8 + 3O2 + heat  3CO2 + 4H2O
Circle the reactants
Underline the products
Is the equation
endothermic or exothermic?
Is the equation balanced? (Does it Show conservation of matter?)
Circle the reactants
Underline the products
Is the equation
endothermic or exothermic?
Is the equation balanced? (Does it Show conservation of matter?) NO
YES
( C:3 H:8 O:6  C:3 H:8 O: 6+4=10)
( Na:2 Cl:2 O:6  Na:2 Cl:2 O:6)

22. Summary – 5 minutes silent writing time
When looking at a chemical equation, how do you determine if it follows the law of conservation of matter?
What is the difference between endothermic and exothermic reactions?
Give an example of an endothermic reaction.
Give an example of an exothermic reaction.

23. Independent Work Name each atom found in the following compounds and determine how many atoms of each element are present:
1) CaF2
2) Be(OH)2
3) NO2
4) Al2(SO4)3
5) NH4NO3
6) S2F2
7) Na2CO3
8) CH4