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ThoughtCo / Hilary Allison Updated on January 24, 2020 A chemical reaction is a process generally characterized by a chemical change in which the starting materials (reactants) are different from the products. Chemical reactions tend to involve the motion of electrons, leading to the formation and breaking of chemical bonds. There are several different types of chemical reactions and more than one way of classifying them. Here are some common reaction types: Oxidation-Reduction or Redox Reaction In a redox reaction,
the oxidation numbers of atoms are changed. Redox reactions may involve the transfer of electrons between chemical species. Direct Combination or Synthesis Reaction In a synthesis
reaction, two or more chemical species combine to form a more complex product. Chemical Decomposition or Analysis Reaction In a decomposition reaction, a compound is broken into smaller chemical species. Single Displacement or Substitution Reaction A substitution or
single displacement reaction is characterized by one element being displaced from a compound by another element. Metathesis or Double Displacement Reaction In a double displacement or metathesis reaction two compounds exchange bonds or ions in order to form different compounds. Acid-Base Reaction An acid-base reaction is a 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: Combustion A combustion reaction is a type of
redox reaction in which a combustible material combines with an oxidizer to form oxidized products and generate heat (exothermic
reaction). Usually, 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: IsomerizationIn an isomerization reaction, the structural arrangement of a compound is changed but its net atomic composition remains the same. Hydrolysis Reaction A hydrolysis reaction
involves water. The general form for a hydrolysis reaction is: The Main Reaction TypesThere are hundreds or even thousands of types of chemical reactions! If you are asked to name the main 4, 5 or 6 types of chemical reactions, here is how they are categorized. The main four types of reactions are direct combination, analysis reaction, single displacement, and double displacement. If you're asked the five main types of reactions, it is these four and then either acid-base or redox (depending who you ask). Keep in mind, a specific chemical reaction may fall into more than one category. Watch Now: How to Assign Oxidation NumbersA chemical reaction is a process or chemical change that transforms one set of substances (the reactants) into another set of substances (the products). The process involves breaking chemical bonds between atoms and forming new bonds, so the number and type of atoms are the same for both reactants and products. The chemical change is described by a chemical equation. There are several types of chemical reactions. Here is look at the four main types of chemical reactions, plus additional key reaction types. 4 Main Types of Chemical ReactionsKeep in mind, there are different names for the reaction types. The four main types of chemical reactions are:
There are many other types of reactions, though. This table summarizes some key points of the main types of chemical reactions:
Let’s take a closer look at the types of reactions and get examples: Synthesis or Direct Combination ReactionIn a synthesis, direct combination, or composition reaction, two (or more) reactants combine to form a more complex product. The general form of the reaction is: A + B → AB An example of a synthesis reaction is the combination of iron and sulfur to form iron(II) sulfide: 8 Fe + S8 → 8 FeS Here are other examples of synthesis reactions:
Decomposition or Analysis ReactionA compound breaks or decomposes into smaller pieces in a chemical decomposition or analysis reaction. The general form of the reaction is: AB → A + B An example of a decomposition reaction is the electrolysis of water to form oxygen and hydrogen: 2 H2O → 2 H2 + O2 Here are additional examples of decomposition reactions:
Single Replacement, Single Displacement, or Substitution ReactionA single replacement, single displacement, or substitution reaction is when one element is displaced from a reactant to form a compound with another element. The reaction has the general form: A + BC → AC + B An example of a single replacement reaction is when zinc combines with hydrochloric acid to form zinc chloride and hydrogen. The zinc replaces or displaces the hydrogen in hydrochloric acid: Zn + 2 HCl → ZnCl2 + H2 Double Replacement, Double Displacement, or Metathesis ReactionWhen the reactant cations and anions “swap partners” the reaction is called a double replacement, double displacement, or metathesis reaction. The general form for a double replacement reaction is: AB + CD → AD + CB An example of a double replacement reaction is the reaction between sodium chloride and silver nitrate to yield sodium nitrate and silver chloride: NaCl(aq) + AgNO3(aq) → NaNO3(aq) + AgCl(s) Combustion ReactionA combustion reaction is the reaction between a fuel and oxygen to form one or more oxides. Because many fuels are carbon-based, carbon dioxide (CO2) is often a product. Sometimes water (H2O) is a product. Here are examples of combustion reactions and their balanced equations:
Acid-Base or Neutralization ReactionAn acid-base reaction is a type of double replacement 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 → H2O + BA The reaction between hydrobromic acid (HBr) and sodium hydroxide is an example of an acid-base reaction: HBr + NaOH → NaBr + H2O Oxidation-Reduction or Redox ReactionRedox stands for reduction and oxidation. The two processes occur together. This type of reaction involves electron transfer between reactants and a change in oxidation number. An example is the reduction of I2 to form I– and oxidation of S2O32- (thiosulfate anion) to form S4O62-: 2 S2O32−(aq) + I2(aq) → S4O62−(aq) + 2 I−(aq) Isomerization ReactionIn an isomerization reaction, the structural arrangement of a compound is changed but its net atomic composition remains the same. For example: CH3CH2CH2CH3 (n-butane) → CH3CH(CH3)CH3 (i-butane) Hydrolysis ReactionA hydrolysis reaction is a reaction in which one or more water molecules is added to a substance. In some cases, this causes both the substance and water molecule to split. The general form of a hydrolysis reaction is: X–(aq) + H2O(l) ↔ HX(aq) + OH–(aq) The reverse reaction is a condensation reaction. In a condensation reaction, water is removed from a substance. How Many Types of Chemical Reactions Are There?Technically, there are hundreds or even thousands of different types of chemical reactions. However, chemistry students usually learn to classify them as 4 main types, 5 main types, or 6 main types. The four main types of chemical reactions are synthesis, decomposition, single displacement, and double displacement. But, remember, some people use different names for these reactions. Other important types of reactions are combustion, acid-base, and redox reactions. It gets even more complicated in organic chemistry, where many reactions have special names. However, these other types of reactions also fit into one of the four main categories! Types of Chemical Reactions WorksheetPractice identifying the four main types of chemical reactions with this worksheet. Download and print the PDF worksheet and answer key. [Types of Chemical Reactions Worksheet] [PDF Answer Key] References
What are the 4 main reaction types?Combination Reaction.. Decomposition Reaction.. Displacement Reaction.. Double Displacement Reaction.. Precipitation Reaction.. What are the five reaction types?The five basic types of chemical reactions are combination, decomposition, single-replacement, double-replacement, and combustion.
What are 4 examples of a chemical reaction?Chemical Change Examples. Combustion.. Oxidation (rusting). Biological decomposition or fermentation.. Cooking an egg.. Photosynthesis.. Chemical decomposition.. Reacting acids and bases together.. Chemical batteries.. What are 6 types of reactions?6 Main Types of Chemical Reactions. synthesis reaction.. decomposition reaction.. single displacement reaction.. double displacement reaction.. combustion reaction.. acid-base reaction.. |