Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Main types of Chemical Reactions A. Composition or Synthesis ReactionElement or compounds react to form JUST ONE PRODUCT. 4 Al + 3O2 2Al2O3 N2O5 + H2O 2HNO3 1. A Group IA or IIA metal may combine with a nonmetal to make a salt. Ex. A piece of lithium metal is dropped into a container of nitrogen gas. Li + N2 Li3N 2. Two nonmetals may combine to form a molecular compound. Ex. P4 + 6Cl2 4PCl3 limited Cl P4 + 10Cl2 4PCl5 excess Cl 3. When an element combines with a compound, you can usually sum up all of the elements on the product side. Ex. PCl3 + Cl2 PCl5 4. Two compounds combine to form a single product. Ex. Sulfur dioxide gas is passed over solid calcium oxide. SO2 + CaO CaSO3 5. A metallic oxide plus carbon dioxide yields a metallic carbonate. (Carbon keeps the same oxidation state) Na2O+ CO2 Na2CO3 6. A metallic oxide plus sulfur dioxide yields a metallic sulfite. (Sulfur keeps the same oxidation state) Na2O + SO3 Na2SO3 7. A metallic oxide plus water yields a metallic hydroxide. Na2O + H2O NaOH 8. A nonmetallic oxide plus water yields an acid. NO2 + H2O HNO3 B. Decomposition ReactionStart off with JUST ONE REACTANT. It breaks down. Heat, electrolysis, or a catalyst is usually necessary. 2K(ClO3) 2KCl + 3O2 Ca(CO3) CaO + CO2 1. A compound may break down to produce two elements. Ex. Molten sodium chloride is electrolyzed. 2NaCl(l) 2Na + Cl2 2. A compound may break down to produce an element and a compound. Ex. A solution of hydrogen peroxide is decomposed catalytically. H2O2 H2O + O2 3. A compound may break down to produce two compounds. Ex. Solid magnesium carbonate is heated. MgCO3 MgO + CO2 4. Metallic carbonates break down to yield metallic oxides and carbon dioxide. Na2CO3 NaO + CO2 5. Metallic chlorates break down to yield metallic chlorides and oxygen. NaClO3 NaCl + O2 6. Sulfurous acid decomposes into water and sulfur dioxide. H2SO3 H2O + SO2 7. Carbonic acid decomposes into water and carbon dioxide. H2CO3 H2O + CO2 C. Single Replacement Reaction – 1. A metal bumps a less active metal out of a compound. Ca + 2Ag(NO3)(aq) 2Ag + Ca(NO3)2(aq) 2. A nonmetal bumps a less active nonmetal out of a compound. Cl2 + 2KI (aq) I2 + 2KCl(aq) 3. Active metals replace less active metals or hydrogen from their compounds in aqueous solution. Use an activity series or a reduction potential table to determine activity. The more easily oxidized metal replaces the less easily oxidized metal. The metal with the most negative reduction potential will be the most active. Ex. Magnesium turnings are added to a solution of iron(III) chloride. Mg + Fe3+ Fe + Mg2+ Ex. Sodium is added to water. Na + H2O Na+ + OH- + H2 4. Active nonmetals replace less active nonmetals from their compounds in aqueous solution. Each halogen will displace less electronegative (heavier) halogens from their binary salts. Ex. Chlorine gas is bubbled into a solution of potassium iodide. Cl2 + I- I2 + Cl- D. Double Replacement- The metals in 2 ionic substances trade places. Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2K(NO3)(aq) 1. Two compounds react to form two new compounds. No changes in oxidation numbers occur. All double replacement reactions must have a "driving force" that removes a pair of ions from solution. A. Formation of a precipitate: A precipitate is an insoluble substance formed by the reaction of two aqueous substances. Two ions bond together so strongly that water can not pull them apart. You must know your solubility rules to write these net ionic equations! Ex. Solutions of silver nitrate and lithium bromide are mixed. Ag+ + Br- AgBr(s) B. Formation of a gas: Gases may form directly in a double replacement reaction or can form from the decomposition of a product such as H2CO3 or H2SO3. Ex. Excess hydrochloric acid solution is added to a solution of potassium sulfite. H+ + SO32- H2O + SO2(g) Ex. A solution of sodium hydroxide is added to a solution of ammonium chloride. OH- + NH4+ NH3 + H2O C. Formation of a molecular substance: When a molecular substance such as water or acetic acid is formed, ions are removed from solution and the reaction "works". Ex. Dilute solutions of lithium hydroxide and hydrobromic acid are mixed. OH- + H+ H2O (HBr, HCl, and HI are strong acids) E. Combustion Reaction2C2H6 + 7O2 4CO2 + 6H2O 1. Elements or compounds combine with oxygen. Nonmetallic hydrides combine with oxygen to form oxides and water. Ex. Carbon disulfide vapor is burned in excess oxygen. CS2 + O2 CO2 + SO2 2. Hydrocarbons or alcohols combine with oxygen to form carbon dioxide and water. Ex. Ethanol is burned completely in air. C2H5OH + O2 CO2 + H2O 3. Nonmetallic sulfides combine with oxygen to form oxides and sulfur dioxide. Ex. Carbon disulfide vapor is burned in excess oxygen. CS2 + O2 CO2 + SO2