KEY TO AP CHEMISTRY EQUATIONS BY TYPE 1968-82, 1985-88, 1990-93, 1995 Double Replacement 1. Hydrogen sulfide is bubbled through a solution of silver nitrate. 1+ + H2S + Ag1+Æ Ag2S + H+ 2. An excess of sodium hydroxide solution is added to a solution of magnesium nitrate. - 2+ OH + Mg2+ Æ Mg(OH)2 3. Solutions of sodium iodide and lead nitrate are mixed. - 2+ I + Pb2+ Æ PbI2 4. A solution of ammonia is added to a solution of ferric chloride. 3+ + NH3 + H2O + Fe3+ Æ NH4 + Fe(OH)3 5. Solutions of silver nitrate and sodium chromate are mixed. + 2- Ag+ + CrO4 Æ Ag2CrO4 6. Excess silver acetate is added to a solution of trisodium phosphate. + 3- Ag+ + PO4 Æ Ag3PO4 7. Manganese(II) nitrate solution is mixed with sodium hydroxide solution. 2+ - Mn + OH Æ Mn(OH)2 8. A saturated solution of calcium hydroxide is added to a solution of magnesium chloride. 2+ - Mg2+ + OH- Æ Mg(OH)2 9. Hydrogen sulfide gas is added to a solution of cadmium nitrate. 2+ + H2S + Cd Æ CdS + H 10. Dilute sulfuric acid is added to a solution of barium acetate. + 2- 2+ - H+ + SO4 + Ba + C2H3O2 Æ BaSO4 + HC2H3O2 11. A precipitate is formed when solutions of trisodium phosphate and calcium chloride are mixed. 3- 2+ PO4 + Ca ÆCa3(PO4)2 12. A solution of copper(II) sulfate is added to a solution of barium hydroxide. 2+ 2- 2+ - Cu2+ + SO4 + Ba + OH Æ Cu(OH)2 + BaSO4 13. Equal volumes of dilute equimolar solutions of sodium carbonate and hydrochloric acid are mixed. + 2- H+ + CO3 Æ HCO3- 14. Solid barium peroxide is added to cold dilute sulfuric acid. + 2- BaO2 +H+ + SO4 Æ BaSO4 + H2O2 15. Excess hydrochloric acid solution is added to a solution of potassium sulfite. + 2- H+ + SO3 Æ H2O + SO2 16. Dilute sulfuric acid is added to a solution of barium chloride. 2- 2+ SO4 + Ba Æ BaSO4 17. A solution of sodium hydroxide is added to a solution of ammonium chloride. + - NH4 + OH Æ NH3 + H2O 18. Dilute hydrochloric acid is added to a solution of potassium carbonate. + 2- H + CO3 Æ H2O + CO2 19. Gaseous hydrogen sulfide is bubbled through a solution of nickel(II) nitrate. 2+ + H2S + Ni Æ NiS + H 20. A solution of sodium sulfide is added to a solution of zinc nitrate. Kristen Henry Jones 1 S2- + Zn2+Æ ZnS 21. Concentrated hydrochloric acid is added to solid manganese(II) sulfide. + 2+ H+ + MnS Æ H2S + Mn2+ 22. Solutions of tri-potassium phosphate and zinc nitrate are mixed. 3- 2+ PO4 + Zn Æ Zn3(PO4)2 23. Dilute acetic acid solution is added to solid magnesium carbonate. 2+ - HC2H3O2 + MgCO3 Æ H2O + CO2 + Mg + C2H3O2 24. Gaseous hydrofluoric acid reacts with solid silicon dioxide. HF + SiO2 Æ H2O + SiF4 25. Equimolar amounts of trisodium phosphate and hydrogen chloride, both in solution, are mixed. 3- + 2- PO4 + H Æ HPO4 26. Ammonium chloride crystals are added to a solution of sodium hydroxide. - - NH4Cl + OH Æ NH3 + H2O + Cl 27. Hydrogen sulfide gas is bubbled through a solution of lead(II) nitrate. 2+ + H2S + Pb2+ Æ PbS + H+ 28. Solutions of silver nitrate and sodium chromate are mixed. + 2- Ag+ + CrO4 Æ Ag2CrO4 29. Solutions of sodium fluoride and dilute hydrochloric acid are mixed. F- + H+ Æ HF 30. A saturated solution of barium hydroxide is mixed with a solution of iron(III) sulfate. 2+ - 3+ 2- Ba2+ + OH- + Fe3+ + SO4 Æ BaSO4 + Fe(OH)3 31. A solution of ammonium sulfate is added to a potassium hydroxide solution. + - NH4 + OH Æ NH3 + H2O 32. A solution of ammonium sulfate is added to a saturated solution of barium hydroxide. + 2- 2+ - NH4 + SO4 + Ba +OH Æ NH3 + H2O + BaSO4 33. Dilute sulfuric acid is added to solid calcium fluoride. + 2- H+ + SO4 + CaF2 Æ CaSO4 + HF 34. Dilute hydrochloric acid is added to a dilute solution of mercury(I) nitrate. - 2+ Cl + Hg2 Æ Hg2Cl2 35. Dilute sulfuric acid is added to a solution of lithium hydrogen carbonate. + - H + HCO3 Æ H2O + CO2 36. Dilute hydrochloric acid is added to a solution of potassium sulfite. + 2- H+ + SO3 Æ H2O + SO2 37. Carbon dioxide gas is bubbled through water containing a suspension of calcium - 2+ carbonate. CO2 + CaCO3 + H2O Æ HCO3 + Ca2+ 38. Excess concentrated sulfuric acid is added to solid calcium phosphate. 2+ 2- H2SO4 + Ca3(PO4)2 Æ H3PO4 + CaSO4 (or Ca + SO4 ) 39. Hydrogen sulfide gas is bubbled into a solution of mercury(II) chloride. 2+ + H2S + Hg Æ HgS + H SingleReplacement 1. A piece of aluminum metal is added to a solution of silver nitrate. Kristen Henry Jones 2 Al + Ag+ Æ Al3+ + Ag 2. Aluminum metal is added to a solution of copper(II) chloride. Al + Cu2+ Æ Al3+ + Cu 3. Hydrogen gas is passed over hot copper(II) oxide. H2 + CuO Æ H2O + Cu 4. Small chunks of solid sodium are added to water. + - Na + H2O Æ Na + OH + H2 5. Calcium metal is added to a dilute solution of hydrochloric acid. + 2+ Ca + H+ Æ Ca2+ + H2 6. Magnesium turnings are added to a solution of iron(III) chloride. Mg + Fe3+ Æ Mg2+ + Fe 7. Chlorine gas is bubbled into a solution of sodium bromide. - - Cl2 + Br Æ Cl + Br2 8. A strip of magnesium is added to a solution of silver nitrate. Mg + Ag+ Æ Mg2+ + Ag 9. Solid calcium is added to warm water. 2+ - Ca + H2O Æ Ca + OH + H2 10. Liquid bromine is added to a solution of potassium iodide. - - Br2 + I Æ Br + I2 11. Chlorine gas is bubbled into a solution of potassium iodide. - - Cl2 + I Æ Cl + I2 12. Lead foil is immersed in silver nitrate solution. Pb + Ag+ Æ Pb2+ + Ag 13. Solid zinc strips are added to a solution of copper(II) sulfate. Zn + Cu2+ Æ Zn2+ + Cu 14. Sodium metal is added to water. + - Na + H2O Æ Na+ + OH + H2 15. A bar of zinc metal is immersed in a solution of copper(II) sulfate. Zn + Cu2+ Æ Zn2+ + Cu Anhydrides 1. Excess water is added to solid calcium hydride. 2+ - H2O + CaH2 Æ Ca + OH or (Ca(OH)2)+ H2 2. Solid lithium hydride is added to water. + - LiH + H2O Æ Li+ + OH- + H2 3. Liquid phosphorus trichloride is poured into a large excess of water. + - PCl3 + H2O Æ H3PO3 + H+ + Cl 4. Solid sodium carbide is added to an excess of water. + - Na4C + H2O Æ C2H2 + Na+ + OH 5. Solid magnesium nitride is added to excess deuterium oxide. Mg3N2 + D2O Æ Mg(OD)2+ ND3 6. Water is added to a sample of pure phosphorus tribromide. + - H2O + PBr3 Æ H3PO3 + H+ + Br 7. Water is added to a sample of pure sodium hydride. Kristen Henry Jones 3 + - H2O + NaH Æ Na+ + OH + H2 8. Dinitrogen trioxide gas is bubbled into water. N2O3 + H2O Æ HNO2 9. Solid phosphorus pentachloride is added to excess water. + - PCl5 + H2O Æ H3PO4 + H + Cl 10. Solid dinitrogen pentoxide is added to water. + - N2O5 + H2O Æ H+ + NO3 11. Sulfur trioxide gas is added to excess water. + 2- SO3 + H2O Æ H+ + SO4 12. Solid sodium oxide is added to water. + - Na2O + H2O Æ Na+ + OH 13. Phosphorus(V) oxytrichloride is added to water. + - POCl3 + H2O Æ H3PO4 + H+ + Cl 14. Water is added to a sample of solid magnesium nitride. H2O + Mg3N2 ÆMg(OH)2 + NH3 15. Solid potassium oxide is added to water. + - K2O + H2O Æ K + OH 16. Solid sodium cyanide is added to water. + - NaCN + H2O Æ HCN + Na+ + OH 17. Trisodium phosphate crystals are added to water. + - 2- - Na3PO4 + H2O Æ Na+ + OH + HPO4 ( or H2PO4 ) 18. Solid lithium oxide is added to excess water. + - Li2O + H2O Æ Li + OH 19. Solid barium oxide is added to distilled water. 2+ - BaO + H2O Æ Ba + OH 20. Solid calcium hydride is added to distilled water. 2+ - CaH2+ H2O Æ Ca + OH or (Ca(OH)2) + H2 Combustion 1. Lithium metal is burned in air. Li + O2 Æ Li2O 2. The hydrocarbon hexane is burned in excess oxygen. C6H14 + O2 Æ CO2 + H2O 3. Gaseous diborane, B2H6, is burned in excess oxygen. B2H6 + O2 Æ B2O3 + H2O 4. A piece of solid bismuth is heated strongly in oxygen. Bi + O2 Æ Bi2O3 5. Solid zinc sulfide is heated in an excess of oxygen. ZnS + O2 Æ ZnO + SO2 6. Propanol is burned completely in air. C3H7OH + O2 Æ CO2 + H2O 7. Excess oxygen gas is mixed with ammonia gas in the presence of platinum. O2 + NH3 –PtÆ NO2 + H2O 8. Gaseous silane, SiH4, is burned in oxygen. Kristen Henry Jones 4 SiH4 + O2 Æ SiO2 + H2O 9. Ethanol is completely burned in air. C2H5OH + O2 Æ CO2 + H2O 10. Solid copper(II) sulfide is heated strongly in oxygen gas. CuS + O2 Æ CuO + SO2 11. Ethanol is burned in oxygen. C2H5OH + O2 Æ CO2 + H2O Redox 1. Iron(III) ions are reduced by iodide ions. 3+ - 2+ Fe3+ + I Æ Fe2+ + I2 2. Potassium permanganate solution is added to concentrated hydrochloric acid. - + - 2+ MnO4 + H + Cl Æ Mn + Cl2 + H2O 3. Magnesium metal is added to dilute nitric acid, giving as one of the products a compound in which the oxidation number for nitrogen is -3. + - + 2+ Mg + H+ + NO3 Æ NH4 + Mg + H2O 4. A solution of potassium iodide is electrolyzed. - - I + H2O Æ I2 + H2 + OH 5. Potassium dichromate solution is added to an acidified solution of sodium sulfite. 2- 2- + 3+ 2- Cr2O7 + SO3 + H Æ Cr + SO4 + H2O 6.