1. Chemical Equations
Chemical change involves a reorganization of the atoms in one or more substances.

2. Chemical Equation A representation of a chemical reaction:
CH4 + O2  CO2 + H2O
reactants products

3. What Drives a Chemical Reaction?
Formation of a solid
Formation of water
Transfer of electrons
Formation of a gas

4. Types of Reactions

5. Combination Reaction
When two or more reactants come together to make one product. Also called Synthesis.
Example:
N2 + H2  NH3
Note that diatomic molecules (Magnificent 7! The Gens) must be diatomic in their elemental form.

6. Decomposition Reaction
When a single compound is broken down into its elements or two products
Example:
H2O  H2 + O2

7. Single Displacement Reaction
When an element and an ionic compound react and the element takes the place of its comparable ion
metals  positive ion
nonmetals  negative ion
Examples:
Mg + FeCl3  MgCl2 + Fe Br2 + FeCl3  FeBr3 + Cl2

8. Mg + FeCl3  MgCl2 + Fe Br2 + FeCl3  FeBr3 + Cl2
Notice!
The neutral atom gets the charge it normally tends to get as an ion when it becomes one.
The products MUST be electronically neutral. Since Mg becomes Mg+2, two Cl ions neutralize it.
The charge on the transition metal stays the same if it remains as an ion (iron is +3 charge in both the reactant and product)

9. Double Displacement Reaction
When two ionic compounds switch their partner ions.
Positive goes with other negative and vice versa.
Switcheroo!
Example:
NaCl + MgBr2  MgCl2 + NaBr
Pb(NO3)2 + Na2SO4  NaNO3 + PbSO4

10. NaCl + MgBr2  MgCl2 + NaBr Pb(NO3)2 + Na2SO4  NaNO3 + PbSO4
Notice!
The reactants and products MUST be electronically neutral
All ions keep their charge from reactants to products
Do not get fooled into thinking that if there are a certain number atoms of an element in the reactants, there will be the same number in the products!
Polyatomic ions are very common in these types of reactions. Make sure you can spot them!

11. Combustion Reactions
When a hydrocarbon (something with C’s and H’s and sometimes O’s – organic molecule) reacts with Oxygen to form water and carbon dioxide and heat energy. 
Example:
CH4 + O2  CO2 + H2O
C4H8 + O2  CO2 + H2O

12. Precipitation Reaction
When a solid precipitate is formed from aqueous solutions being mixed.
Same a double displacement.
When a solid is dissolved in water, the ions separate.
Some ionic compounds do not separate – solubility rules!

13. Solubility Rules
All common salts of the Group 1 elements and the NH4+ ion are soluble.
All common nitrates and acetates are soluble
All binary compounds of the Group 17 elements (other than F) with metals are soluble EXCEPT those of silver (Ag), mercury (Hg), and lead (Pb).
All sulfates are soluble EXCEPT those of Calcium (Ca), strontium (Sr), barium (Ba), mercury (Hg), and lead (Pb).
Except for those in Rule 1, carbonates (CO32-), hydroxides (OH-), oxides (O2-), and phosphates (PO43-) are insoluble.

14. Solubility Rules – Table Form
Soluble Compounds
Important Exceptions
Compounds containing:
NO3-
none
C2H3O2-
alkali metals (group 1)
NH4+
Cl-
Salts of Ag+, Hg22+, and Pb2+
Br- I-
SO42-
Salts of Ca2+, Sr2+, Ba2+, Hg22+, and Pb2+

15. Solubility Rules – Table Form
Insoluble Compounds
Important Exceptions
Compounds containing:
S2-
Salts of NH4+, the alkali metal cations, and Ca2+. Sr2+, and Ba2+
OH-
CO32-
Salts of NH4+, the alkali metal cations,
PO43-

16. Forming Water – Acid Base
When an acid reacts with a base, water forms
Acids produce H+ in water
Bases produce OH- in water
Example:
HNO3 + KOH  HOH + KNO3

17. Oxidation-Reduction Reactions
When electrons are transferred
OXIDATION STATES!
What is the oxidation state of each element in the following
Na3N
NaNO3
N2O

18. Redox Reactions Synthesis and Decomposition Combustion
Single Displacement
Mg + O2  MgO

19. What type of equation are each of the following reactions?
P + O2  P2O5
C3H5O + O2  CO2 + H2O
NH4NO3  N2O + H2O
Fe2O3 + C  Fe + CO
CO2 + H2O  H2CO3
CuNO3 + Na2SO4  Cu2SO4 + NaNO3

20. Check Your Answers P + O2  P2O5 Combination
C3H5O + O2  CO2 + H2O Combustion
NH4NO3  N2O + H2O Decomposition
Fe2O3 + C  Fe + CO Single Displacement

21. Check Your Answers CO2 + H2O  H2CO3 Combination
CuNO3 + Na2SO4  Cu2SO4 + NaNO3
Double Displacement

22. Predict the Products!
Predict the products of the following reactions. It may help to determine what kind of reaction it is first…
Al + O2 
C3H6 + O2 
LiCl + CuSO4 
NaCl + F2 

23. Check Your Answers Al + O2  Al2O3 C3H6 + O2  CO2 + H2O
LiCl + CuSO4  CuCl2 + Li2SO4
NaCl + F2  NaF + Cl2

24. Reaction Type Interpretive Art
Your job will be to create some sort of interpretive art for EACH type of chemical reaction (there are 5).
Interpretive art includes poetry (Haiku), short story, drawing, dance, song, etc.

25. Balancing makes me happy
Haiku
Poetry of 3 lines. 5 syllables in the first line, 7 in the second line, 5 in the third.
Chemistry so fun
Balancing makes me happy
Atoms rearrange

26. Balancing Chemical Equations
A representation of a chemical reaction:
CH4 + O2  CO2 + H2O
reactants products

27. Molecular rep of a rxn
Notice that there are 4 hydrogen atoms in the reactants and only 2 in the products.
Notice that there are only 2 oxygen atoms in the reactants and 3 in the products

28. Chemical Equation A representation of a balanced chemical reaction:
CH O2  CO H2O
reactants products

29. Molecular rep of a rxn

30. Chemical Equation CH4 + 2O2  CO2 + 2H2O
The equation is balanced – there are the same number of each atom on each side of the arrow.
1 molecule of methane reacts with 2 molecules of oxygen
to produce
1 molecule of carbon dioxide and 2 molecules of water

31. To Balance Equations
Start with the element that is most complex, usually
Make sure the same numbers of atoms of that element are on both sides of the equation
You CANNOT change the formula of a molecule in an equation
You must change the COEFFICIENT of the molecule to make there be the same numbers

32. Balance the Reaction 1 Ca + AlCl3  CaCl2 + Al
Chlorine is the most complex
There are 3 Cl’s in the reactants and 2 Cl’s in the products
The least common multiple between 3 and 2 is…6
In order to make 6 Cl’s on each side, put the coefficient 2 in front of the AlCl3 and the coefficient 3 in front of the CaCl2.

33. Balance the Reaction 1 Ca + 2AlCl3  3CaCl2 + Al
Now you have changed the number of Aluminum’s in the reactants to 2. There is only 1 Al in the products
In order to make there be 2 Al’s in the products, put the coefficient 2 in front of the Al
You have also changed the number of Calcium’s in the products to 3. There is only 1 Ca in the reactants
Put the coefficient 3 in front of the Ca.

34. Balance the Reaction 1 3Ca + 2AlCl3  3CaCl2 + 2Al
Check to see that there are equal numbers of each atom on each side of the reaction…
The reaction is Balanced!!

35. Balance the Reaction 2 C2H5OH + O2  CO2 + H2O
Hydrogen is the most complex
There are 6 H’s in the reactants and only 2 in the products
In order to make 6 H’s in the products, put the coefficient 3 in front of the H2O

36. Balance the Reaction 2 C2H5OH + O2  CO2 + 3H2O
Carbon is the next most complex
There are 2 C’s in the reactants and only 1 in the products
In order to make 2 C’s in the products, put the coefficient 2 in front of the CO2

37. Balance the Reaction 2 C2H5OH + O2  2CO2 + 3H2O
Now you have changed the numbers of Oxygen atoms in the products – there are 7 O’s
Changing the number of C2H5OH’s will force you to change the coefficients on the products
One of the O’s is used up in the C2H5OH, so there are 6 O’s that need to be accounted for by the O2’s.
Put the coefficient 3 in front of the O2 so there are 7 total O’s in the reactants.

38. Balanced Reaction 2! C2H5OH + 3O2  2CO2 + 3H2O
Check to make sure that there are the same numbers of each atom on each side!

39. Which of the following correctly describes the balanced chemical equation given below? There may be more than one true statement. If a statement is incorrect, explain what is incorrect about it.
4Al + 3O2  2Al2O3
I. For every 4 atoms of aluminum that react with 6 atoms of oxygen, 2 molecules of aluminum oxide are produced.
II. For every 4 moles of aluminum that react with 3 moles of oxygen, 2 moles of aluminum(III) oxide are produced.
III. For every 4 grams of aluminum that react with 3 grams of oxygen, 2 grams of aluminum oxide are produced.

40. Which of the following correctly balance the chemical equation given below?
CaO + C  CaC2 + CO2
1. CaO2 + 3C  CaC2 + CO2
2. 2CaO + 5C  2CaC2 + CO2
3. CaO + (2.5)C  CaC2 + (0.5)CO2
4. 4CaO + 10C  4CaC2 + 2CO2

41. Notice
The number of atoms of each element must be the same on both sides of a balanced equation.
Subscripts must not be changed to balance an equation.
A balanced equation tells us the ratio of the number of molecules that react and are produced in a chemical reaction.
Coefficients can be fractions, but they are usually given as lowest integer multiples.
Trial and error is a valid method to balance a chemical equation.

42. Balance the following Reactions
N H2  NH3
H2O  H O2
Mg + FeCl3  MgCl Fe
Br FeCl3  FeBr Cl2

43. Check your answers N2 + 3H2  2NH3 2H2O  2H2 + O2
3Mg + 2FeCl3  3MgCl2 + 2Fe
3Br2 + 2FeCl3  2FeBr3 + 3Cl2

44. Balance the following reactions
NaCl + MgBr2  MgCl2 + NaBr
Pb(NO3)2 + Na2SO4  NaNO3 + PbSO4
CH4 + O2  CO2 + H2O
C4H10 + O2  CO2 + H2O

45. Check Your Answers 2NaCl + MgBr2  MgCl2 + 2NaBr
Pb(NO3)2 + Na2SO4  2NaNO3 + PbSO4
CH4 + 2O2  CO2 + 2H2O
C4H /2O2  4CO2 + 5H2O or
2C4H O2  8CO2 + 10H2O

46. Balance the Reactions Al + O2  Al2O3 C3H8 + O2  CO2 + H2O
LiCl + CuSO4  CuCl2 + Li2SO4
NaCl + F2  NaF + Cl2

47. Check Your Answers 4Al + 3O2  2Al2O3 C3H8 + 5O2  3CO2 + 4H2O
2LiCl + CuSO4  CuCl2 + Li2SO4
2NaCl + F2  2NaF + Cl2