** Special Reaction Types** - these special types may classify as one of the 4 types as well
A Combustion reaction - or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame . Fuels of interest often include organic compounds (especially hydrocarbons ) in the gas , liquid or solid phase.
In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen or fluorine , and the products are compounds of each element in the fuel with the oxidizing element. For example:
CH
4
+ 2 O
2
→ CO
2
+ 2 H
2
O + energy
** Notes -The products of any combustion of a hydocarbon (CH) or carbohydrate (CHO) is always carbon dioxide (CO
2
) and water (H
2
O) as seen in above reaction.
B - Oxidation-Reduction or Redox Reaction
In a redox reaction the oxidation numbers of atoms are changed. Redox reactions involve the transfer of electrons between chemical species. Electrons are lost by one specie (oxidized) and gained by another (reduced)
The reaction that occurs when In which Cu +2
(aq)
(copper ion) is reduced to Cu
(s)
(copper metal)
Al
(s)
(aluminum metal) is oxidized to Al
+3
(aq)
(aluminum ion) provides an example of a redox reaction:
Al
(s)
+ Cu
+2
(aq)
→ Al
+3
(aq)
+ Cu
(s)
** notes synthesis and decomposition reaction can commonly be redox-reactions as well. **
**Combustion and single replacement reactions are always redox-reactions.**
C - Acid-Base Reaction or Neutralization Reaction
An acid-base reaction is type of double displacement reaction that occurs between an acid and a base. The H + ion in the acid reacts with the OH ion in the base to form water and an ionic salt:
HA + BOH → H
2
O + BA
The reaction between hydrobromic acid (HBr) and sodium hydroxide is an example of an acidbase reaction:
HBr + NaOH → NaBr + H
2
O
** note – acid-base neutralization reaction are essentially metathesis (double replacement) reactions with H +1 combining with OH -1 to form water and the salt formed from the cation/anion present.