1. Determining Products of Reactions AP Chemistry 2012-2013
Chemical Reactions
Determining Products of Reactions
AP Chemistry

2. Types of Reactions Metathesis – no transfer of electrons
Double Replacement
Precipitation Reactions
Solids
Gases
Acid-Base Reactions

3. Types of Reactions Continued
Oxidation-Reduction Reactions – transfer of electrons
Some types of redox reactions include
Single Replacement
Combustion
Synthesis
Decomposition

4. Writing the equations NET IONIC ONLY Balanced for mass and charge
Examples

5. Two Elements as Reactants
Synthesis
Be sure to assign the most common oxidation states to the elements
Examples
Solid zinc is heated in chlorine gas.
Solid sulfur is burned in oxygen

6. Example Reactions
Answers
Zn + Cl2  ZnCl2
S + O2  SO2

7. Single Reactant Must be a Decomposition
When unsure, break the compound into its elements
Most do not completely decompose but produce
Ionic salts and
oxide gases
Example
Solid calcium carbonate is heated
A piece of solid potassium nitrate is heated

8. Example Reactions
Answers
CaCO3  CaO + CO2
2 KNO3  2 KNO2 + O2

9. Water is a Reactant Three variations
Pure metal or metal hydride in water makes a base and hydrogen gas.
Sodium metal is added to distilled water
Lithium hydride is added to distilled water
A metal oxide in water will produce a base.
Solid barium oxide is added to water.
A nonmetal oxide in water will produce an acid.
Solid dinitrogen pentoxide is added to water.
Carbon dioxide gas is bubbled through water.

10. Examples Answers Na + 2 H2O  Na+ + 2 OH- + H2
LiH + 2 H2O  Li OH- + H2
BaO + H2O  Ba OH-
N2O5 + H2O  2 H NO3-
CO2 + H2O  H2CO3

11. Mixture of two salt solutions
Precipitation Reactions – KNOW YOUR SOLUBILITY RULES AND COMMON IONS
Net ionic and balanced
Examples
A solution of silver nitrate is added to a solution of potassium iodide
Solutions of lead(II) nitrate and tri-potassium phosphate are mixed

12. Examples
Ag+ + I-  AgI
3 Pb PO4 3-  Pb3(PO4)2

13. Combustion of carbon compounds
Combustion is the reaction with oxygen
Produces carbon dioxide and water when enough oxygen is present
Examples
Propane is burned in air.
Carbon disulfide is burned in excess oxygen.

14. Examples
C3H O2  3 CO H2O
CS O2  CO SO2

15. Single replacement Transition metal placed in a solution
Oxidation-reduction reaction
Metal will always be oxidized M+x
Neutral conditions
Ion in solution will be reduced
Examples
Solid manganese flakes are placed in a solution of copper (II) sulfate
Iron filings are placed in a solution of iron (III) sulfate.

16. Examples Mn + Cu2+  Mn2+ + Cu Fe + 2 Fe3+  3 Fe 2+ Fe  Fe 2+ + 2e-
Fe e-  Fe 2+

17. Single replacement (2) Acidic conditions with an oxoacid Examples
Anion of the oxoacid will be reduced to an oxide gas and water will form
Examples
Copper is immersed in dilute nitric acid
Lead is immersed in concentrated warm sulfuric acid

18. Examples Cu + H+ + NO3-  Cu2+ + NO + H2O
Pb + H+ + HSO4-2  Pb SO2 + H2O

19. Formation of complex ions
Look for transition metal ions in solution with NH3, OH-, CN-, or SCN-
Don’t worry about how many you put on the metal ion
Usually combine in 1, 2, 4, or 6
Add the charges together to determine the charge on the whole ion
Example
Excess ammonia is added to a solution of silver nitrate
Ag+ + NH3  Ag(NH3)2+

20. More examples of complex ions
A solution of sodium cyanide is added to a solution of iron(II) chloride
Fe CN-  Fe(CN)6 4-
Charges are determined by adding all the ions in the complex
x -1 = -4

21. Videos of reactions – alkali metals and water
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