1. Chemical Reactions
Unit 5

2. Chemical Reactions 1
Chemical change occurs when bonds break and new bonds form
New substances are produced
Chemical reactions involve two main kinds of changes that you can observe
Formation of new substances
Precipitate- solid that is formed during a chemical reaction
Changes in energy
A. Endothermic- energy is absorbed
B. Exothermic- energy is released

3. Open system-matter can enter or exit
Types of Systems
Open system-matter can enter or exit
Closed system- matter can’t enter or exit

4. C +O2  CO2 Chemical Equations
Chemical Equation- representation of a chemical reaction that uses symbols to show the relationship between the reactants and products
Reactants- what is put into a reaction
Product- what forms after a reaction occurs
C +O2  CO2
Reactants Yields Product

5. Types of Chemical Reactions
Unit 5: Chemical Reactions
Types of Chemical Reactions

6. Synthesis
Synthesis reaction- two or more substances combine to make one new compound
A + B → AB

7. Decomposition
Decomposition- single compound is broken down into two or more compounds
AB → A + B

8. Single Replacement Reactions
Single replacement- one element takes the place of another element
AB + C → AC + B

9. AB + CD → AC + BD Double Replacement
Double replacement- two substances change places with each other
AB + CD → AC + BD

10. Combustion
A compound containing carbon and hydrogen react with oxygen gas to produce carbon dioxide and water
Equation: CxHx + O > CO2 + H2O

11. Cut and Paste Types of Chemical Reactions Tuesday November 7
Directions:
Cut out the 4 types of reactions “words” and each reaction.
Glue the four types of reaction words along the top of the construction paper.
Sort through each reaction and glue it under the correct type.
Due at the END of the period. If you don’t finish, take it home for HW.
Types of Chemical reactions Quiz THURSDAY
Rubric:
Neatness Accuracy Following Direction

12. Reaction Types Lab Wednesday November 8

13. Counting atoms & Law of Conservation of Mass
Unit 5: Chemical Reactions
Counting atoms & Law of Conservation of Mass

14. Law of Conservation of Mass
Mass is neither created nor destroyed and both sides of the equation must be equal
Scientists know that there must be the same number of atoms on each side of the reaction.
To balance the chemical equation, you must add coefficients in front of the chemical formulas in the equation.
You cannot add or change subscripts!
H2O and H2O2 are NOT the same thing!
Lets WATCH:

15. Law of Conservation of Mass Article Thursday November 9, 2017
Read the Article.
Write the correct answer to answers on the BACK of your visual representation.
Use plenty of color in your illustration.

16. Numbers
Subscript: small number after the symbol that tells you how many of that one element
Coefficient: large number before the compound that tells you how much compound is present
To find how many of each element:
Multiply the coefficient by the subscript for each element

17. How many atoms are in each Compound?
H2CO3 =___H ___C ___O
H20 = ___ H ___0
HCl = ___H ___ Cl
ZnCl2 = ___Zn ___Cl
AgNO3 =___ Ag ___N ___O
FeCl2 = ___Fe ___Cl

18. How many atoms are in each Compound?
2H2CO3 =___H ___C ___O
3H20 = ___ H ___0
4HCl = ___H ___ Cl
2ZnCl2 = ___Zn ___Cl
3AgNO3 =___ Ag ___N ___O
4FeCl2 = ___Fe ___Cl

19. Balancing Equations

20. Rules to balancing equations
Rule 1- the superscript or the two in co2 cannot be changed
Rule 2- You can add a coefficient (the three) in 3CO2
Rule 3- the atoms on both sides must be equal

21. Example

22. Let’s Practice page ___#1
____Mg ____O > ____MgO
Mg= Mg=
O= O=

23. #2
____Ca + ____O > ____CaO Ca= Ca= O= O=

24. #3
____N2 + ____H > ____NH3
N= N=
H= H=

25. #4
____Cu2O + ____C > ____Cu + ____CO2 Cu= Cu= O= O= C= C=

26. #5
____H2O > ____H2O + _____ O2
H= H=
O= O=

27. Balancing Equation WebQuest
Wednesday November 15

28. Open/ Closed Lab Thursday November 16

29. Rate of Reaction

30. Energy and Reaction
All chemical reactions need a certain amount of activation energy to get started.
Activation energy is a certain amount of energy needed to start a chemical reaction
Chemist can control rates of reactions by changing factors such as
surface area,
temperature and
concentration
Presence of a catalysts and inhibitors

31. Reactions
Endothermic
Exothermic

32. Rate of Reactions Increase Temperature Increase Surface area
Heating a substance, it’s particles move faster
Faster-moving particles increase rate reaction in two ways:
Particle come in contact more often. More chances for a rxn to happen
Have more energy
Example: storing food in the refrigerator because keeping foods cold slows down those reactions
Breaking the solid into smaller pieces, more particles are exposed and the reaction happens faster.
Example: chewing food breaks it into smaller pieces that your body can digest more easily and quickly

33. Increase Concentration
The amount of substance in a given volume
Increasing concentration of reactants supplies more particles to react.

34. Catalysts
Inhibitors
Material that increases the rate of reaction by LOWERING activation energy.
Controls the rate of a reaction to change the activation energy
does NOT permanently changed by a reaction
Material used to decease the rate of reaction
Works by preventing reactants from coming together
Example: preservatives added to food product to prevent them from becoming stale or spoiling

35. Investigating rate of reactions Wednesday November 29
LAB
Investigating rate of reactions
Wednesday November 29