1. Chemical Reactions
Reaction Types

2. Write and classify balanced chemical equations from written descriptions of reactions.
Include: polyatomic ions
Predict the products of chemical reactions, given the reactants and type of reaction.
Additional KEY Terms

3. Chemical equation – contains all necessary info about a reaction (like a recipe).+ +

4. The Law of Conservation of Mass:
In any chemical reaction matter cannot be created or destroyed.
H2 (g) + O2 (g) H2O (g) 2 2 H H O H H O O H H H
We call this equation unbalanced because the atoms are not conserved. H O

5. Balancing Rules:
You cannot change the formula of any reactant or product.
You can only change the coefficients in front of the reactants and products. 3
H2O

6. 2 HCl + MgBr2 MgCl2 + HBr 2 H: 1 H: 1 (2) = 2 (2) = 2 Cl: 1 Cl: 2
Mg: 1 Mg: 1
Br: Br: 1
(2) = 2
(2) = 2
(2) = 2
(2) = 2
BALANCED

7. 2 2 K(NO3) + Mg Mg(NO3)2 + K K: 1 K: 1 NO3: 1 NO3: 2 Mg: 1 Mg: 1
(2) = 2
(2) = 2
(2) = 2
BALANCED

8. + + 2 K2O + Cl KCl + O (s) 2 2 (g) 4 2 (g) +1 -2 +1 -1 potassium
Solid potassium oxide and chlorine gas react to produce potassium chloride and oxygen gas.
potassium
oxide
potassium
chloride +
chlorine +
oxygen 2
K2O Cl KCl + O
(s) 2 2
(g) 4 2
(g)

9. Many reactions are similar.
Chemists have classified the 5 types of reactions.
BIG PICTURE IDEA:
If you know the reactants - you can guess the type of reaction AND predict the products.

10. Key Words Synthesis reactions Decomposition reactions
Single replacement reactions
Double replacement reactions
Combustion reactions

11. 2 2 4 3 2 K + Cl2 KCl Fe + O2 Fe2O3 Synthesis Reactions (Combination):
2 or more substances react to form a single substance.
A + B  C 2
K Cl KCl
Fe O Fe2O3 2 4 3 2

12. C  A + B 2 2 2 3 CO2 CO + O2 Al2S3 Al + S Decomposition Reactions:
A single compound splits apart, into two or more simpler compounds.
C  A + B
CO CO O2
Al2S Al S 2 2 2 3

13. A + BC  AC + B 2 2 2 2 Single Replacement Reactions:
One element replaces another element in a compound.
More active elements replace less active elements.
A + BC  AC + B 2 2
I CuCl Cl CuI
Ba K(NO3) K Ba(NO3)2 2 2

14. AB + CD  AD + CB 2 2 3 3 BaF2 + LiBr BaBr2 + LiF
Double Replacement Reactions:
2 compounds split and exchange positive ions
AB + CD  AD + CB 2 2
BaF LiBr BaBr LiF
HCl AlBr3 HBr AlCl3 3 3

15. CxHy + O2  CO2 + H2O 8 7 3 5 3 4 C7H6O + O2 CO2 + H2O
Combustion Reactions:
Oxygen reacts with a carbon compound to produce water, carbon dioxide and heat.
CxHy + O2  CO H2O
C7H6O O CO H2O
C3H O CO H2O 8 7 3 5 3 4

16. Synthesis or combination A + B  C
Decomposition C  A + B
Single replacement A + BC  B + AC
Double replacement AC + BD  AD + BC
Combustion reactions CxHy + O2  CO2 + H2O

17. CAN YOU / HAVE YOU?
Write and classify balanced chemical equations from written descriptions of reactions.
Include: polyatomic ions
Predict the products of chemical reactions, given the reactants and type of reaction.