Types of Chemical Reactions Single Replacement Reactions Double Replacement Reactions Combustion Reactions

Recall Synthesis Reactions Two or more substances combine to form one substance. The general form is A + X AX Decomposition Reactions One substance reacts to form two or more substances. The general form is AX  A+X

Single Replacement Reactions A metal will replace a metal ion in a compound. The general form is A + BX  AX + B A nonmetal will replace a nonmetal ion in a compound. The general form is Y+BX  BY + X

Single Replacement Reactions Examples: Ni + AgNO3 NiNO3 + Ag Nickel replaces the metallic ion Ag+ (metal replaces metal ion) The silver becomes free silver and the nickel becomes the nickel (II) ion. Ni + AgNO3  Ag + Ni(NO3)2 Balance the equation: Ni + 2AgNO3  2Ag + Ni(NO3)2

Thermite Reaction Steve Spangler Video Thermite

Thermite Reaction Al + Fe2O3  Aluminum will replace iron (III) as was seen in the video. Iron (III) becomes Fe and aluminum metal becomes Al3+. 2Al + Fe2O3  Al2O3 + 2Fe

Double Replacement Reactions Ions of two compounds exchange places with each other. Reactants must be two ionic compounds, in aqueous solution The general form is AX+BY = AY + BX

Remember the Demonstration!!!!!!!! Word - Lead (II) Nitrate + Potassium Iodide --> Potassium Nitrate + Lead Iodide Skeletal - Pb(NO3)2 (aq) + 2KI (aq) --> 2KNO3 (aq) + PbI2 (s) What occurred??? This is a double displacement reaction

Double Replacement NaOH + CuSO4  The Na+ and Cu2+ switch places. Na+ combines with SO42- to form Na2SO4. Cu2+ combines with OH- to form Cu(OH)2 NaOH + CuSO4  Na2SO4 + Cu(OH)2 2NaOH + CuSO4  Na2SO4 + Cu(OH)2

Double Replacement CuSO4 + Na2CO3  Cu2+ combines with CO32- to form CuCO3. Na+ combines with SO42- to form Na2SO4. CuSO4 + Na2CO3  CuCO3 + Na2SO4

Double Replacement Reactions Think about it like “foil”ing in algebra, first and last ions go together + inside ions go together Example: AgNO3(aq) + NaCl(s)  AgCl(s) + NaNO3(aq) Another example: K2SO4(aq) + Ba(NO3)2(aq)  KNO3(aq) + BaSO4(s) 2

Recognition You need to be able to recognize which reaction is taking place

Practice Examples: Synthesis H2 + O2 ® H2O ® Zn + H2SO4 ® HgO ® KBr + Cl2 ® AgNO3 + NaCl ® Mg(OH)2 + H2SO3 ® Synthesis Decomposition Single Displacement Double Replacement

Combustion Reactions Combustion means “add Oxygen” Normally, a compound composed of only C, H, (and maybe O) is reacted with oxygen – usually called “burning” If the combustion is complete, the products will be CO2 and H2O. If the combustion is incomplete, , the products will be CO (or possibly just C) and H2O.

Combustion Reaction When a substance combines with oxygen, a combustion reaction results. The combustion reaction may also be an example of an earlier type such as 2Mg + O2  2MgO. The combustion reaction may be burning of a fuel.

Combustion Reactions Combustion reactions involve light and heat energy released. Natural gas, propane, gasoline, etc. are burned to produce heat energy. Most of these organic reactions produce water and carbon dioxide.

Combustion Reaction When hydrocarbon compounds CxHx are burned in oxygen, the products are water and carbon dioxide. CH4 + O2  CO2 + H2O CH4 + 2O2  CO2 + 2H2O Demonstration

Combustion Reactions Generally combustion reactions involve the burning of a Hydrocarbon (CxHx) in Oxygen. Other elements can also burn with Oxygen 2Mg + O2  2MgO+ Energy 2H2 + O2  2H2O+ Energy (basis behind fuel cell energy) P4 + 5O2  P4O10 + Energy (matches)

Practice Classify each of the following as to type: H2 + Cl2  2HCl Synthesis Ca + 2H2O  Ca(OH)2 + H2 Single Displacement

Practice 2CO + O2  2CO2 2KClO3  2KCl + 3O2 Synthesis and Combustion Decomposition

Practice FeS + 2HCl  FeCl2 + H2S Zn + 2HCl  ? ZnCl2+ H2 Double Replacement Zn + 2HCl  ? ZnCl2+ H2 Single Displacement