A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Majorly, chemical reactions include changes that only involve the positions of electrons in the breaking and forming of chemical bonds between atoms, with no change to the nuclei, and can often be described by a chemical equation. The feature covers the various types of chemical reactions with the help of animations.
1) Synthesis Reaction
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In a synthesis reaction, a complex structure forms as a result of the combination between two simpler substances. The compound formed as a result of this reaction can be ionic or molecular. This means that it can be either a reaction of metal(s) with non-metal(s) (ionic) or amongst two or more non-metals (molecular). The general form of synthesis reaction is:
A + B → AB
A real life example of this reaction is of Hydrogen gas which burns in air (reacts with oxygen) to form water.
2) Decomposition Reaction
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A decomposition reaction is the opposite of a synthesis reaction, where a more complex substance breaks down into its more simple parts. The second animation shows how Hydrogen peroxide is catalytically decomposed by the potassium iodide. Another classic example of this type of reaction is the decomposition of hydrogen peroxide into oxygen and hydrogen gas. The general form of a decomposition reaction is:
AB → A + B
Electrolysis of water and Carbonic acid in soda are some real life examples of the decomposition reaction.
3) Single Replacement Reaction
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A single replacement reaction is a type of oxidation-reduction reaction in which an element in a compound is replaced by another element. The animation shows the Copper-Iron single replacement reaction which takes place as follows:
Cu(s) + AgNO3(aq) → Ag(s) + Cu(NO3)2(aq)
The general form of a single replacement reaction is:
AB + C → A + BC
4) Oxidation Reduction Reaction (Redox)
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Redox (reduction-oxidation) reactions include all chemical reactions in which atoms have their oxidation state changed. Oxidation is the loss of electrons or an increase in oxidation state by a molecule, atom, or ion. Reduction is the gain of electrons or a decrease in oxidation state by a molecule, atom, or ion. The animation shows Sodium [Na] and fluorine [F] bonding ionically to form sodium fluoride. Sodium loses its outer electron to give it a stable electron configuration, and this electron enters the fluorine atom exothermically. The oppositely charged ions are then attracted to each other. The sodium is oxidized, and the fluorine is reduced.
5) Acid Base Reaction
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An acid base reaction mainly involves the transfer of protons from one acid to another base. When a proton is removed from an acid, the resulting species is termed that acid’s conjugate base. When the proton is accepted by a base, the resulting species is termed that base’s conjugate acid. In an acid base reaction, acids act as proton donors and bases act as proton acceptors.