1. Classifying, Writing, and Balancing Equations

2. There are certain molecules that are made up of two atoms. They are never alone in nature. They are called diatomic molecules!

3. These diatomic molecules are: H 2, O 2, N 2, F 2, Cl 2, Br 2, I 2

4. A. Synthesis Reactions

5. Direct union of two elements will produce a binary compound.

6. element + element  compound Synthesis Reaction General Formula

7. Example 1: a. Classify the following equation. Na + Cl 2  NaCl element compound 22 b. Balance the equation. Classification: synthesis reaction

8. Example 2: Aluminum + Chlorine Al+Cl 2  AlCl 3 322

9. B. Decomposition Reactions

10. Decomposition reactions are the reverse of synthesis reactions. *A binary compound will decompose into two elements.

11. compound  element + element Decomposition Reaction General Formula

12. Example 1: a. Classify the following equation. Nb 2 O 5  Nb + O 2 compoundelement 42 b. Balance the equation. Classification: decomposition reaction 5

13. Example 2: Sodium nitride is heated. Na 3 N  Na+N2N2 62

14. C. Single Displacement Reactions

15. During single displacement reactions, one element replaces another element in a compound. *Cations only replace cations and anions only replace anions.

16. element + compound  element + compound Single Displacement Reaction General Formula

17. Example 1: a. Classify the following equation. Br 2 + NaI  NaBr + I 2 compound element 2 b. Balance the equation. Classification: single displacement reaction 2 element

18. Example 2: Aluminum is added to hydrochloric acid. Al  AlCl 3 + H2H2 +HCl

19. Example 2: Aluminum is added to hydrochloric acid. Al  AlCl 3 + H2H2 2 2 +HCl6 3

20. D. Double Displacement Reactions

21. During double displacement reactions, the cation of one compound replaces the cation in another compound.

22. compound + compound  compound + compound Double Displacement Reaction General Formula

23. Example 1: a. Classify the following equation. CaBr 2 + Na 3 PO 4  Ca 3 (PO 4 ) 2 + NaBr compound 3 b. Balance the equation. Classification: double displacement reaction 2 compound 6

24. Example 2: Aluminum nitrate is added to barium oxalate. Al(NO 3 ) 3  Al 2 (C 2 O 4 ) 3 + Ba(NO 3 ) 2 + BaC 2 O 4

25. Example 2: Aluminum nitrate is added to barium oxalate. Al(NO 3 ) 3  Al 2 (C 2 O 4 ) 3 +Ba(NO 3 ) 2 2 +BaC 2 O 4 3 3

26. E. Combustion Reactions

27. A combustion reaction is the reaction of a hydrocarbon and oxygen to yield carbon dioxide and water.

28. compound + element  compound + compound Combustion Reaction General Formula hydrocarbon + oxygen  CO 2 + H 2 O

29. Example 1: a. Classify the following equation. C 3 H 8 + O 2  CO 2 + H 2 O elementcompound 3 b. Balance the equation. Classification: combustion reaction 5 compound 4

30. Example 2: Ethane (C 2 H 6 ) is burned. C2H6C2H6  CO 2 +H2OH2O 2 +O2O2 7 64