1. Chemical Reactions

2. Chemical Reaction
the process by which one or more substances are changed into one or more different substances

3. REACTANTS the starting substances in a chemical reaction (the stuff on the left)

4. PRODUCTS the final substances in a chemical reaction (the stuff on the right)

5. General Formula for Reactions
A + B  C Reactants yields Products

6. Law of Conservation of Mass/Matter
Mass/Matter can not be created nor destroyed, simply changed from 1 form to another

7. EQUATIONS
CH O2 CO H2O

8. REPRESENTATION OF PHYSICAL STATES IN EQUATIONS You may see these in book problems
(g) = gas
(l) = liquid
(cr) = solid (stands for crystalline)
(aq) = substance dissolved in water

9. WRITING BALANCED EQUATIONS
STEP 1: Write all of the atoms in the reactants and the products (in the same order)
STEP 2: Put * next to the atom in step 1, if an element occurs more than once on one side of a reaction
STEP 3: Balance the equation (get the same # of atoms of each element on each side). You can only do this by changing coefficients!

10. WARNING!!!
Never
Ever
CHANGE THE SUBSCRIPT

11. Hints for Balancing Balance metals first Then balance polyatomics
Then balance non-metals
Last, balance hydrogens

12. Hints for Balancing If an element is by itself, balance it last
Watch for even or odds, balance accordingly
Don’t forget your diatomics in transcribed problems
Don’t forget to Kriss Kross and use ( )

13. Hints for Balancing
1st, balance anything that is found in 1 product/reactant
Then, balance anything that is found in 2 or more products / reactants

14. Reaction of Zinc with HCl
Please balance the equation
__Zn + __HCl à __ZnCl2 + __H2
Zn = 1
H = 1
Cl = 1
Zn = 1
H = 2
Cl = 2

15. Combustion of ethane C2H6
Please balance the equation
__C2H6 + __O2 à __CO2 + __H2O
C = 2
H = 6
O = 2
C = 1
H = 2
*O = 3

16. Zinc + Hydrochloric Acid
Please write the reaction

17. Writing Balanced Equations When Given Words Only
STEP 1: Write out the symbols
STEP 2: Balance your charges (if needed)
STEP 3: Check for diatomics
STEP 4: Balance Equation

18. Hints for Balancing
Don’t forget your diatomics in transcribed problems
Don’t forget to Kriss Kross and use ( )

19. Combustion of Acetone (CH3)2CO
Please write the reaction
(CH3)2CO(l) + O2(g) à CO2(g) + H2O(g)

20. HOMEWORK
Pg. 228 #1-12
Pg. 243 #43, 45, 46, 58
Worksheet

21. two or more substances combine to form one new substance
SYNTHESIS
two or more substances combine to form one new substance

22. SYNTHESIS
A + B  AB
Na + Cl2  NaCl
Pb(IV) + O2 
Pb2O4

23. Info on Synthesis Reactions
Also known as “combination” reactions
Always form compounds
Generally give off lots of energy
Can be reversed (decomposition)

25. when a substance breaks up into simpler substances
DECOMPOSITION
when a substance breaks up into simpler substances

26. Decomposition
AB  A + B
NaCl  Na + Cl2
Pb2O4 
Pb + O2

27. Info on Decomp Reactions
Energy is usually need to make these reactions happen
Often hard to predict products unless the substance breaks into its ionic components (or memorize some basic types of reactions)
Often are the cause of explosions

28. Types Decomp Reactions
Metallic Carbonates
When heated, metallic carbonates decompose into metallic oxides and carbon dioxide
BaCO3 --> BaO + CO2
Cu2CO3 --> Cu2O + CO2

29. Types Decomp Reactions
Metallic Chlorates
When heated, metallic chlorates decompose into metallic chlorides and oxygen
KClO3 --> KCl + O2
Zn(ClO4)2 --> ZnO + O2

30. Types Decomp Reactions
Metallic Hydroxides
When heated, metallic hydroxides decompose into metallic oxides and water
Ca(OH)2 --> CaO + H2O
Mn(OH)4 --> Mn2O4 + H2O

31. Types Decomp Reactions
Metallic Oxides
When heated, metallic oxides decompose into the metal and oxygen
K2O --> K + O2
Pb2O4 --> Pb + O2

32. Decomp of Trinitrotoluene
2C7H5N3O6 (s) -->
3N2(g) + 7CO2(g) + 5H2O(g) + 7C(s)
2 moles of TNT decompose to produce 15 moles of hot, expanding gases…that is why it is so powerful!

34. one element displaces another in a compound
SINGLE DISPLACEMENT
one element displaces another in a compound

35. Single Displacement Reaction

36. AB + C  AC + B or CB + A Single Displacement NaBr + Cl2  NaCl + Br2
(NH4)2S + O2 
(NH4)2O + S

37. Info on Single Replacement
Also known as single displacement reactions
Only elements with a higher activity can replace other elements (use table on pg. 217)
Nonmetals can replace other non-metals, but is usually limited to halogens (active decreases down table)

38. Types Single Replacement
Metals
More active metal atoms will replace less active metal ions from compounds
Cu + AgNO3 --> Ag + Cu(NO3)2
Ag + Cu(NO3) --> No Reaction

39. Types Single Replacement
Halogens
More active halogen atoms will replace less active halogen ions from compounds
F2 + NaCl --> Cl2 + NaF
Cl2 + FCl --> No Reaction

40. Types Single Replacement
Halogens
More active halogen atoms will replace less active halogen ions from compounds
F2 + NaCl --> Cl2 + NaF
Cl2 + FCl --> No Reaction

46. negative portions of two compounds are switched
DOUBLE DISPLACEMENT
the positive or
negative portions of two compounds are switched

47. Double Displacement AB + CD  AD + CB
NaBr + Pb2S3  Na2S + PbBr3
K2SO4 + Ba(OH)2
KOH + BaSO4

48. Info on Double Replacement
Also known as double displacement reactions
Reactants must be two ionic compounds in aqueous solution
Cations switch positions
Usually produces a precipitate (ppt)

49. For Double Replacement to Occur one is Usually True
Also known as double displacement reactions
Reactants must be two ionic compounds in aqueous solution
Cations switch positions
Usually produces a precipitate (ppt)

50. hydrocarbon reacts with oxygen to form carbon dioxide and water
COMBUSTION (aka OXIDATION)
hydrocarbon reacts with oxygen to form carbon dioxide and water

51. Writing Out Equations STEP 1: Determine type of rxn
STEP 2: Write out symbols
STEP 3: Kriss-Kross where necessary
STEP 4: Diatomics
STEP 5: Balance the equation

52. Common Words Decomposes = breaks apart Combusts = a combustion rxn
Reacts with = A + B
“To form” or “to get”= 
Yields = 
Displaces = have a single D. rxn
And = plus (+)

53. Common Words Decomposes = breaks apart Combusts = a combustion rxn
Reacts with = A + B
“To form” or “to get”= 
Yields = 
Displaces = have a single D. rxn
And = plus (+)

54. HOMEWORK
Pg. 231 #13-22