1. Chemical reactions

2. We will be talking about the following types of reaction?
Precipitation
Oxidation
Decomposition and synthesis
Acid-base neutralization reaction

3. The goal To balance a chemical equation
Represent a precipitation reaction use a molecular model
Identify oxidation reaction and understand how they function
Associate known chemical reactions with decomposition or synthesis reactions.
Recognize an acid base chemical reaction based on its equation
Determine the molecular formula of the salt formed during an acid and base neutralization reaction.
Determine the quantity of reagents and products in a reaction.

4. Chemical equations Reactants products
Atoms cannot be destroyed or created
The exact atoms that appear on the left, must appear on the right.

6. 1.Balancing equations
Write down all the atoms, grouped by molecule for the reactant
Write down all the atoms, grouped by molecule for the products
Begin trying to balance everything, remember you must multiply whole molecules

7. Examples
H2SO NaOH H2O Na2SO4

8. Al + HCl H2 + AlCl3

9. NH3 + O2 NO + H2O

10. Tips and Tricks PRACTICE
Start with elements that appear only once on each side
Leave elements to the end
Remember lowest common multiples (LCM’s)
If the element is odd on one side and even on the other , multiply the odd side by 2
PRACTICE

11. C6H12O O CO H2O

12. Fe + Cl2 → FeCl3

13. TiCl4 + H2O → TiO2 + HCl

14. Ba3N2 + H2O → Ba(OH)2 + NH3

15. Extra sheet up front

16. 2.Precipitation reactions
A reaction where a precipitate forms after two aqueous solutions are mixed together. Precipitate: A solid that falls out of a liquid.

18. 2KI(aq) + Pb(NO3)2(aq)  PbI2(s) + 2KNO3(aq)

19. Represent the following reactions using the particle model
AgNO3 (aq) + KCl (aq) → AgCl (s) + KNO3(aq)
BaCl2(aq) + K2SO4(aq)  BaSO4(s) + 2 KCl(aq)
CuSO4(aq) + 2NaOH(aq) → Na2SO4(aq) + Cu(OH)2(s)

20. Exam type question
Represent the following reaction using the particle theory. Silver nitrate is mixed with sodium bromide to produce a strong electrolyte and silver bromide which is slightly soluble.

21. Exam type question
Represent the following reaction using the particle theory. Mixing of two strong electrolytes produces a precipitate of Alumimun hydroxide in a sodium chloride solution.

22. Exam type question
Represent the following reaction using the particle theory. Mixing of two strong electrolytes produces a precipitate of Calcium sulphate in a lithium nitrate solution.

23. Represent the following reaction using the particle theory
Represent the following reaction using the particle theory. Silver nitrate is mixed with sodium bromide to produce a strong electrolyte and silver bromide which is slightly soluble.

24. 3. Oxidation reaction Also known as a combustion(burning) reaction
A reaction in which oxygen gas(O2) is a reactant. Always produces heat.

25. Fe (s) + O2Fe2O3

27. 2 Cu + H2O +CO2 + O2  Cu(OH)2 + CuCO3

28. C6H12O6 +
6 O2 =
6 CO2
6 H2O

30. Respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O 

31. Ethanol (C2H5O) burns with oxygen to create water and carbon dioxide
Ethanol (C2H5O) burns with oxygen to create water and carbon dioxide. Write the balanced equation for this reaction.

32. Propane(C3H8) burns to produce carbon dioxide and water
Propane(C3H8) burns to produce carbon dioxide and water. Write the balance equation

33. Acetylene (C2H2) is oxidized to produce carbon dioxide and water
Acetylene (C2H2) is oxidized to produce carbon dioxide and water. Write the balanced equation.

34. Hydrogen gas undergoes oxidation to produce water
Hydrogen gas undergoes oxidation to produce water. Write the balance chemical reaction.

35. P285 # 3

36. 4. Decomposition and synthesis
A decomposition reaction is the breakdown of a compound into two or more components. AB  A + B Example: Hydrolysis of water 2 H2O(l)  2H2(g) + O2(g)

37. Synthesis
Synthesis is a chemical reaction in which elements or compounds combine to produce one or more complex compounds.
A + B  AB
Example: O2(g) + H2(g)  H2O
N2(g) + H2(g)  NH3(g)

38. Is the following reaction synthesis or decomposition? Why?
Respiration C6H12O6(s) + 6O2  6CO2 + 6H2O

39. Is the following reaction synthesis or decomposition? Why?
Photosynthesis 6CO2 + 6H2O  C6H12O6(s) + 6O2

40. Is the following reaction synthesis or decomposition? Why?

41. Digestion
Your body takes complex molecules, such as complex sugars, protein, and fats and break them down into simpler molecules
Breakdown of lactose
C12H22O11+H2O→C6H12O6+C6H12O6+ heat.

42. Breakdown of proteins

43. worksheet
P. 287 #4

44. 5+ 6 Acid Base Neutralization equations
Acid-base neutralization is a chemical reaction that occurs when an acid and a base are mixed together. The products are a salt and water.
Acid + base salt + water
The pH becomes 7

45. Acid Base Neutralization equations
Acid + base salt + water
Steps
Write the dissociation equation
Find your water ( H+ and OH-)
Put the other ions together to form a salt

47. Write the dissociation equations for the following
NH4OH
KOH
Ca(OH)2
Al(OH)3

48. practice
KOH + H2SO4
HCl + Ca(OH)2
NaOH + CH3COOH

49. Q , p635

50. Salt
A salt is an electrolyte composed of a cation and anion that are not H+ or OH-.
It generally has a pH of 7 when dissolved in water.

51. 7. Stoichiometry
The coefficients in a balanced equation give the stoichiometry of the equation
It tells you how many molecules of one type react with the other type and how many molecules they produce

52. Stoichiometric calculations
By knowing how much of one compound is used or produced, you can determine the amounts for the rest of the equation
Possible because of conservation of mass and stoichiometric relations

54. Steps Read the question Balance the equation
Set-up cross multiplication
Top line – from the question
Bottom line – from the equation

55. The Cross Multiplication
Top line
An x from your question (moles or grams)
The moles or grams mentioned in the word problem
Bottom line
If top line is moles, only coefficient
If top line is grams, coefficient and molar mass

56. 3 types Mass to mass Mass to moles Moles to moles
Solve them all the same way

57. Examples moles-moles
Calculate the number of moles O2 needed to burn 10 moles of methane.
CH4 + O2 CO2 + H2O

58. Example moles - grams
Calculate how many grams of methane must be burnt with oxygen to produce 3 moles of CO2.

59. Example mass-mass
Using the following equation how much copper could be extracted from 900g of copper (II) oxide?
3 CuO + 2NH3 N2 + 3Cu + 3H2O

60. How many grams of sodium sulfate will be formed if you start with 200 grams of sodium hydroxide and you have an excess of sulfuric acid?
2 NaOH + H2SO4  2 H2O + Na2SO4

61. How many grams of lithium nitrate will be needed to make 250 grams of lithium sulfate, assuming that you have an adequate amount of lead (IV) sulfate to do the reaction?
Pb(SO4)2 + 4 LiNO3  Pb(NO3)4 + 2 Li2SO4

62. 6.5,
6.7,
6.9,
6.11,
6.13,