Video:What Are Types of Chemical Reactions?with Anne Marie Helmenstine
All types of chemical reactions involve the motion of electrons, leading to the formation and breaking of chemical bonds. Learn more about the different types of chemical reactions.See Transcript
Transcript:What Are Types of Chemical Reactions?Chemical reactions involve the motion of electrons, leading to the formation and breaking of chemical bonds. There are several different types of chemical reactions. Some common reaction types are:
Types of Chemical Reactions: Direct Combination or Synthesis ReactionIn a synthesis reaction two or more chemical species combine to form a more complex product.
The combination of iron and sulfur to form iron (II) sulfide is an example of a synthesis reaction:
8 Fe + S8 --> 8 FeS
Types of Chemical Reactions: Chemical Decomposition or Analysis ReactionIn a decomposition reaction a compound is broken into smaller chemical species.
The electrolysis of water into oxygen and hydrogen gas is an example of a decomposition reaction:
2 H2O --> 2 H2 + O2
Types of Chemical Reactions: Single Displacement or Substitution ReactionA substitution or single displacement reaction is characterized by one element being displaced from a compound by another element.
An example of a substitution reaction occurs when zinc combines with hydrochloric acid. The zinc replaces the hydrogen:
Zn + 2 HCl --> ZnCl2 + H2
Types of Chemical Reactions: Metathesis or Double Displacement ReactionIn a double displacement or metathesis reaction two compounds exchange bonds or ions in order to form different compounds.
An example of a double displacement reaction occurs between sodium chloride and silver nitrate to form sodium nitrate and silver chloride.
NaCl(aq) + AgNO3(aq) --> NaNO3(aq) + AgCl(s)
Types of Chemical Reactions: Acid-Base ReactionAn 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:
The reaction between hydrobromic acid and sodium hydroxide is an example of an acid-base reaction:
HBr + NaOH --> NaBr + H2O
Types of Chemical Reactions: Oxidation-Reduction or Redox ReactionIn a redox reaction the oxidation numbers of atoms are changed. Redox reactions may involve the transfer of electrons between chemical species.
As an example, the reaction that occurs when iodide (I2) is reduced to Iodine (I-) and the thiosulfate (S2O32-) is oxidized:
2 S2O32−(aq) + I2(aq) --> S4O62−(aq) + 2 I−(aq)
Types of Chemical Reactions: CombustionUsually in a combustion reaction oxygen combines with another compound to form carbon dioxide and water. An example of a combustion reaction is the burning of naphthalene:
C10H8 + 12 O2 ---> 10 CO2 + 4 H2O
Types of Chemical Reactions: IsomerizationIn an isomerization reaction, the stuctural arrangement of a compound is changed but its net atomic composition remains the same.
Types of Chemical Reactions: Hydrolysis ReactionA hydrolysis reaction involves water. The general form for a hydrolysis reaction is:
X-(aq) + H2O(l) <--> HX(aq) + OH-(aq)
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