1. RCD Pacing UNIT 4 PHYSICAL SCIENCE

2. Types of Reactions(*New Test Material)
Four main types:
Synthesis
Decomposition
Single replacement
Double replacement

3. Decomposition AB  A + B Opposite of synthesis reaction
Rxn in which a compound breaks down into 2 or more simpler substances
General equation:
AB  A + B
Example:
CaCO2  CaO + CO2

4. Single Replacement A + BC  B + AC
Rxn in which one element takes the place of another element in a compound
General equation:
A + BC  B + AC
Example:
Cu + 2AgNO3  2Ag + Cu(NO3)2

5. Double Replacement AB + CD  AD + CB
Rxn where 2 different compounds exchange positive ions and form two new compounds
General equation:
AB + CD  AD + CB
Example:
Pb(NO3)2 + 2 KI  PbI2 + 2KNO3

6. Synthesis A + B  AB -General equation: Example: 2Na + Cl2  2NaCl
-Two or more substances react to form a single substance
-General equation:
A + B  AB
Example:
2Na + Cl2  2NaCl

7. Combustion Reaction
Combustion occurs when a hydrocarbon reacts with oxygen to produce carbon dioxide and water.
CH4 + O2  CO2 + H2O

8. PRACTICE! Types of Chemical Reactions Worksheet 1-4 identifying.
1-10 ONLY IDENTIFY- we will work on balancing tomorrow 

9. Warm-Up Set 4, #1 1.___A + B  AB 2.___AB + CD  AD + CB
3.___A + BC  B + AC
4.___AB  A + B
Identify the 4 equations above.
Decomposition, Double Replacement, Single Replacement and Synthesis

10. Conservation of Mass and Energy
In a reaction there are 5 grams of Carbon in the reactants. How many grams of Carbon would be in the products? 5!
Why?
Matter (mass) can not be created or destroyed, but it can be rearranged.

11. Ex. Pure Carbon burns according to the following reaction:
Conservation of Mass
Ex. Pure Carbon burns according to the following reaction:
C + O2  CO2
CO2 is a gas, carbon is not created or destroyed, it simply changes from a solid to a gas

12. Rates of Reaction Don’t copy- lets talk…
What makes a reaction speed up or slow down?
When you eat food, do you want your energy now or later?
What breaks down the food in your body to release energy?

13. Now YOU get to practice counting atoms! NOT FUN time!!  Math REVIEW 
Guess WHAT !?!?!?
Now YOU get to practice counting atoms!
NOT FUN time!! 
Math REVIEW 

14. Warm-Up Set 4, #2
1) Count the number of atoms on each side of the equation. Identify the type of reaction and try to balance it. Remember, list the elements, count and recount 
CaCO2  CaO + CO2
2Na + Cl2  2NaCl

15. Chemistry and Energy
Making a bond STORES energy.
BREAKING a bond releases energy.
Catalysts SPEED up the rate of a reaction.

16. Two types of Reactions Endothermic Reactions:
Absorbs energy from its surroundings
Feels “cold” to the touch

18. Two types of Reactions Exothermic Reactions:
Releases energy to its surroundings, usually as heat.
Ex. Combustion reactions

21. Reaction Rate
The rate of a reaction tells you how fast the reaction is going.
Factors that affect reaction rates include: temperature, surface area, concentration, stirring and catalysts

22. Demos Five ways to speed up a chemical reaction (5 minutes)
Glow Stick Demo - Rates of reaction (5 minutes)
Endothermic Reaction (3 minutes)
Gummibear sacrifice (Exothermic Reaction) (3 minutes)
Diet coke and Menthos (2 minutes)