1. Balancing Chemical Equations

2. CA Standards
Students know how to describe chemical reactions by writing balanced equations.

3. Law of Conservation of Mass
In ordinary chemical reactions, the total mass of reacting substances is equal to the total mass of products
All atoms on the reactant side must appear on the product side, and in equal numbers
No new elements may appear
No elements may disappear

4. There are five main signs that indicate a chemical reaction has taken place:
release
input
change in color
production of new
gases or vapor
change in odor
input or release
of energy
difficult to reverse

5. Balancing Chemical Equations
CH4 + 2 O2  CO H2O
Reactants Products
1 C atom C atom
4 H atoms H atoms
4 O atoms O atoms

6. Unbalanced and Balanced EquationsH Cl Cl H Cl Cl H H
H2 + Cl2  HCl
(unbalanced)
H2 + Cl2  2 HCl
(balanced)
reactants products H Cl
reactants products H Cl 2 1 2 2 2 1 2 2

7. Synthesis Reactions
1. ___CaO + ___H2O  ___Ca(OH)2 2. ___P4 + ___O2  ___P2O5 3. ___Ca + ___O2  ___CaO 4. ___Cu + ___S8  ___ CuS 6. ___S8 + ___O2  ___SO2 7. ___H2 + ___N2  ___NH3 8. ___H2 + ___Cl2  ___HCl 9. ___Ag + ___S8  ___Ag2S 10. ___Cr + ___O2  ___Cr2O3 11. ___Al + ___Br2  ___AlBr3 12. ___Na + ___I2  ___NaI 13. ___H2 + ___O2  ___H2O 14. ___Al + ___O2  ___Al2O3

8. Decomposition Reactions
15. ___BaCO  ___BaO ___CO2
16. ___MgCO  ___MgO ___CO2
17. ___K2CO  ___K2O ___CO2
18. ___Zn(OH)  ___ZnO ___H2O
19. ___Fe(OH)  ___FeO ___H2O
20. ___Ni(ClO3)  ___NiCl ___O2
21. ___NaClO  ___NaCl ___O2
22. ___KClO  ___KCl ___O2
23. ___H2SO  ___H2O ___SO3
24. ___H2CO  ___H2O ___CO2
25. ___Al2O  ___Al ___O2
26. ___Ag2O  ___Ag ___O2

9. Double Replacement Reactions
35. ___AlI ___HgCl  ____AlCl ____HgI2(ppt)
36. ___HCl ___NaOH  ___NaCl ___H2O
37. ___BaCl ___H2SO4  ___BaSO ___HCl
38. ___Al2(SO4) ___Ca(OH)  ___Al(OH) ___CaSO4
39. ___AgNO ___K3PO  ___Ag3PO ___KNO3
40. ___CuBr ___AlCl  ___CuCl ___AlBr3
41. ___Ca(C2H3O2) ___Na2CO  ___CaCO ___NaC2H3O2
42. ___NH4Cl ___Hg2(C2H3O2)2  ___NH4 C2H3O ___Hg2Cl2
43. ___Ca(NO3) ___HCl  ___CaCl ___HNO3
44. ___FeS ___HCl  ___FeCl ___H2S
45. ___Cu(OH) ___HC2H3O  ___Cu(C2H3O2) ___H2O
46. ___Ca(OH) ___H3PO  ___Ca3(PO4) ___H2O
47. ___CaBr ___KOH  ___Ca(OH) ___KBr

10. Combustion Reactions
48. ___CH4 + ___O2  ___CO2 + ___H2O 49. ___C2H6 + ___O2  ___CO2 + ___H2O 50. ___C3H8 + ___O2  ___CO2 + ___H2O 51. ___C4H10 + ___O2  ___CO2 + ___H2O 52. ___C5H12 + ___O2  ___CO2 + ___H2O 53. ___C6H14 + ___O2  ___CO2 + ___H2O 54. ___C2H4 + ___O2  ___CO2 + ___H2O 55. ___C2H2 + ___O2  ___CO2 + ___H2O 56. ___C6H6 + ___O2  ___CO2 + ___H2O