1. Good Morning!
Please pick up a note packet and chemical equations vocabulary sheet
Also take out your reference packets
Announcements:
I have graded a lot of your work, but PowerSchool was down this weekend for maintenance  Will get them in ASAP
Unit 2 Grade Recovery – due by Friday

2. Chemical
Equations

3. Chemical Equations
Chemical equations represent chemical reactions (changes).

4. All chemical reactions:
Have two parts:
Reactants - the substances you start with
Products - the substances you end up with
Reactants ® Products

5. Describing chemical reactions:
Atoms aren’t created or destroyed. The atoms are just rearranged.
Can be described several ways -
In a sentence:
Copper reacts with chlorine to form copper (II) chloride.
In a word equation:
Copper + chlorine ® copper (II) chloride
In formulas:
Cu(s) + Cl2(g) ® CuCl2(aq)

6. Symbols used in equations
indicates a reversible reaction.
shows that heat is supplied to the reaction.
, is used to indicate a catalyst used supplied, in this case, platinum.

7. What is a catalyst?
A substance that speeds up a reaction without being changed by the reaction.
Enzymes are biological or protein catalysts.

8. Reaction Energy
All chemical reactions are accompanied by a change in energy. 
Exothermic - reactions that release energy to their surroundings (usually in the form of heat).
Endothermic - reactions that need to absorb heat from their surroundings to proceed.

9. Balancing Equations
Equations must obey the law of conservation of matter.
To balance equations, place numbers in front of elements and compounds (coefficients).
NEVER CHANGE SUBSCRIPTS!
Counting atoms:
Mg3(PO4)2
3 Mg atoms
2 P atoms
8 O atoms

10. Balancing Equations Al(C2H3O2)3 1 Al atom 6 C atoms 9 H atoms
6 O atoms
3Al2(SO4)3
6 Al atoms
9 S atoms
36 O atoms

12. Balancing Equations 2 2
___ H2(g) + ___ O2(g) ---> ___ H2O(l)

13. Practice
1. Zn + HCl → ZnCl2 + H2 Zn + 2 HCl → ZnCl2 + H2 2. F2 + NaBr → NaF + Br2 F2 + 2 NaBr → 2 NaF + Br2 3. LiCl + O2 → LiClO3 2 LiCl + 3 O2 → 2 LiClO3

14. Balancing Equations Practice
4. AgNO3 + MgCl2 → AgCl + Mg(NO3)2
5. CaBr2 + K3PO4 → Ca3(PO4)2 + KBr
6. CH4 + O2 → CO2 + H2O
7. C4H10 + O2 → CO2 + H2O
8. MgCO3 → MgO + CO2

15. ANSWERS 4. 2AgNO3 + MgCl2 →2 AgCl + Mg(NO3)2
5. 3 CaBr2 + 2 K3PO4 → Ca3(PO4)2 + 6 KBr
6. CH4 + 2 O2 → CO2 + 2 H2O
7. 2 C4H O2 → 8 CO H2O
8. MgCO3 → MgO + CO2

16. Diatomic elements There are 7 elements that never want to be alone.
They form diatomic molecules.
H2 , N2 , O2 , F2 , Cl2 , Br2 , I2

17. H N O F Cl Br I

18. Word Equations Fe2S3 (s) + HCl(g) ® FeCl3 (s) + H2S(g)
1) Solid iron (III) sulfide reacts with gaseous hydrogen chloride to form iron (III) chloride and hydrogen sulfide gas.
Fe2S3 (s) + HCl(g) ® FeCl3 (s) + H2S(g)
Fe2S3 + 6 HCl ® 2FeCl3 + 3H2S

19. Word Equations
2) Nitric acid (HNO3) reacts with sodium carbonate to form water, carbon dioxide and sodium nitrate.
HNO3 + Na2CO3 ® NaNO3 + H2O + CO2
2 HNO3 + Na2CO3 ® 2 NaNO3 + H2O + CO2

20. 4Ag (s) +2H2S (g) + O2 (g) ®2Ag2S (s) + 2H2O
3) A silver spoon tarnishes. The solid silver reacts with hydrogen sulfide and oxygen in the air to make solid silver sulfide, the black material we call tarnish and water.
4Ag (s) +2H2S (g) + O2 (g) ®2Ag2S (s) + 2H2O

21. ___ Al(s) + ___ Br2(l) →___ AlBr3(s)
4) Aluminum metal reacts with liquid bromine to form solid aluminum bromide
___ Al(s) 2
+ ___ Br2(l) 3
→___ AlBr3(s) 2

22. 5 Main Types of Chemical Reactions
1) Synthesis reactions
Element + Element →Compound
2Li + Br2  2 LiBr
Compound + Compound  Compound
SO2 + H2O  H2SO3

23. A simulation of the reaction: 2H2 + O2 ® 2H2O

24. Practice Complete and balance the following: H2 + Br2 → Mg + Cl2 →
Mg + O2 →
K + S →
Al + O2 →

25. Answers H2 + Br2 → 2 HBr Mg + Cl2 → MgCl2 2 Mg + O2 → 2 MgO
2 K + S → K2S
4 Al + 3 O2 → 2 Al2O3

26. Synthesis Demonstration

27. Decomposition Reactions
decompose = fall apart
one compound (reactant) falls apart into two or more elements or compounds.
Usually requires energy
AB ® A + B
2NaCl Na + Cl2
CaCO CaO + CO2

28. Decomposition Reactions
A) Binary Compounds
Made up of only two elements
Breaks apart into its elements
H2O →
NaCl →
HgO →

29. Decomposition Reactions
If the compound has more than two elements you must memorize the products
Follow the guide in your packet
B) Metallic Carbonates (CO32-)
MCO3 → MO + CO2
CaCO3 →
CaCO3 → CaO + CO2
Na2CO3 →
Na2CO3 → Na2O + CO2

30. Decomposition Reactions
C) Metallic hydrogen carbonate → metallic carbonate + CO2 + H2O MHCO3 → MCO3 + CO2 + H2O NaHCO3 → 2NaHCO3 → Na2CO3 + CO2 +H2O Mg(HCO3)2 → Mg(HCO3)2 → MgCO3 + CO2 + H2O

31. Decomposition Reactions
D) Metallic hydroxides → metallic oxides + water MOH → MO + H2O LiOH → 2LiOH → Li2O + H2O Ca(OH)2 → Ca(OH)2 → CaO + H2O

32. Decomposition Reactions
E) Metallic chlorates → Metallic chlorides + O2 MClO3 → MCl + O2 KClO3 → 2KClO3 →2KCl + 3O2 Mg(ClO3)2 → Mg(ClO3)2 → MgCl2 + 3O2

33. Decomposition Reactions
This is a decomposition reaction that you will do in lab
H2O2 →
2H2O2 → 2H2O + O2

34. Decomposition Reactions
Practice:
K2CO3 →
KHCO3 →
KOH →
KClO3 →
KCl →

35. Decomposition Demonstration Second Decomposition Demonstration

36. Single Replacement Also referred to as single displacement
One element replaces another
Reactants must be an element and a compound.
You must use the activity chart to determine if the reaction will occur.
Metals will replace metals (and hydrogen).
Nonmetals will replace nonmetals.

37. Single Replacement A + BC ® AC + B
2Na + SrCl2 ® Sr + 2NaCl (metal-metal)
F2 + 2LiCl ® 2LiF + Cl2 (nonmetal-nonmetal)

38. Single Replacement A) Metal- Metal 1. Al + Fe(NO3)2 →
2Al + 3Fe(NO3)2 →2 Al(NO3)3 + 3Fe
2. Ca + AgNO3 →
Ca + 2AgNO3 → Ca(NO3)2 + Ag
3. Cu + KCl →
Cu + KCl → NR
4. Mg + ZnCl2 →
Mg + ZnCl2 → MgCl2 + Zn

39. Single Replacement B) Metal – H2O Na + H2O → Na + H2O → NaOH + H2
Ca + H2O →
Ca + 2H2O → Ca(OH)2 + H2
Ag + H2O →
Ag + H2O → NR

40. Single Replacement C) Metal + Acid (H….) Zn + HCl →
Zn + 2HCl → ZnCl2 + H2
Mg + HCl →
Mg + 2HCl → MgCl2 + H2
Ca + HNO3 →
Ca + 2HNO3 → Ca(NO3)2 + H2
Au + HCl →
Au + HCl → NR

41. Single Replacement D) Nonmetal – Nonmetal Cl2 + HBr →
Cl2 + 2HBr → 2HCl + Br2
F2 + CaBr2 →
F2 + CaBr2 → CaF2 + Br2
I2 + KF →
I2 + KF → NR
Br2 + NaCl →
Br2 + NaCl → NR

42. Single Replacement Demonstration Second Single Replacement Demonstration

43. Combustion 1. CH4 + O2 → CH4 +2O2 ® CO2 + 2H2O
A reaction in which a hydrocarbon reacts with oxygen and always produces carbon dioxide and water.
Combustion reactions are exothermic
1. CH4 + O2 →
CH4 +2O2 ® CO H2O

44. Combustion C3H8 + O2 → C3H8 + 5O2 → 3CO2 + 4H2O C4H10 + O2 →
C6H12O6 + O2 →
C6H12O6 + 6O2 → 6CO2 + 6H2O

45. The charcoal used in a grill is basically carbon
The charcoal used in a grill is basically carbon. The carbon reacts with oxygen to yield carbon dioxide. The chemical equation for this reaction is C + O2  CO2

46. Combustion Demonstration Second Combustion Demonstration

47. Double Replacement AB + CD ® AD + CB ZnS + 2HCl ® ZnCl + H2S
Two ions replace each other.
Reactants must be two ionic compounds
AB + CD ® AD + CB
ZnS HCl ®
ZnCl + H2S
AgNO3 + NaCl ®
AgCl + NaNO3

48. Double Replacement CaCl2 + Li2CO3 → CaCl2 + Li2CO3 → CaCO3 + 2LiCl
Na2SO4 + BaCl2 →
Na2SO4 + BaCl2 → 2NaCl + BaSO4
HCl + NaOH →
HCl + NaOH → NaCl + H2O
Pb(NO3)2 + K2Cr2O7 →
Pb(NO3)2 + K2Cr2O7 → PbCr2O7 + 2KNO3

49. Double Replacement Demonstration

50. Classify the following
Synthesis
H2 + O2 ®
H2O ®
Decomposition
AgNO3 + NaCl ®
Double replacement
Zn + H2SO4 ®
Single replacement
HgO ®
Decomposition
C4H10 +O2 ®
Combustion
Mg(OH)2 + H2SO3 ®
Double replacement

51. Summary An equation: Describes a reaction
Must be balanced because to follow Law of Conservation of Mass
Can only be balanced by changing the coefficients.
Has special symbols to indicate state, and if catalyst or energy is required.
Can describe 5 different types of reactions.