Types of chemical reactions Lesson 12

Types of chemical reactions 1. Combustion Reaction The reaction of a substance with oxygen, producing oxides and energy Fuel + oxygen  oxides + energy AB + oxygen  common oxides of A and B (ex AO, BO)

Common oxides include C = CO2(g) H = H2O(g) S = SO2(g) N =NO2(g)

Example 2C3H6 (g) + 9O2(g)  6CO2(g) + 6H2O(g)

Incomplete combustion occurs when there is not sufficient oxygen Incomplete combustion occurs when there is not sufficient oxygen. When this occurs 4 products are produced instead of the usual H2O and CO2. Incomplete combustion also produces CO(g) and C(s). This is commonly seen when lighting an acetylene torch. 3C2H2­(g) + 3O2(g)  2CO2(g) + 3H2­O(g) + 2CO(g) + 2C(s)

2. Synthesis Reaction -A chemical reaction in which two or more substances combine to form a more complex substance. A + B  AB Example: 2CO(g) + O2(g) pt 2CO2(g)

3. Decomposition reaction -A chemical reaction in which a compound is broken down into two or more simpler substances. AB  A + B Example: The decomposition of water. 2H2O(l) + electricity 2 H2(g) + O2(g)

Chemical reactions in solution A Solution is a homogenous mixture in which a pure substance, called the solute, is dissolved in another pure substance called the solvent.   The solution is often an aqueous solution which is a solution where water is the solvent.

4. Single Displacement reaction -A reaction of an element with a compound to produce a new element and a new compound. The reaction will only occur if the element is higher on the reactivity series than the metal in the compound. A + BC  AC + B Example: Cu(s) + 2AgNO3(aq)  2Ag(s) + Cu(NO3)2(aq)

5. Double displacement reaction - A reaction in which aqueous ionic compounds rearrange cations and anions, resulting in the formation of new compounds. AB + CD  AD + CB Example: Pb(NO3)2 (aq) + 2KI (aq)  PbI2 (s) + 2KNO3 (aq)

Double displacement is likely to occur if; - a precipitate is produced - a gas is produced - a acid base neutralization occurs

Examples 2As + 3O2  2As2O3 KClO4  KCl + 2O2 Type of reaction? KClO4  KCl + 2O2 Zn(s) + CuCl2(s)  Will it occur? Look at the table.

Cu(s) + ZnCl2(s)  will it occur MgCl2(aq) + Ca(OH)2(aq) 