In a chemical reaction, the atoms of the starting species called reactants rearrange to form new substances which are the products of the chemical reaction. The identities of the atoms involved in the reaction remain the same. Their number also stays the same before and after the reaction.
FURTHER EXPLANATION
In a chemical reaction, bond breaking and bond forming happen.
During the reaction the chemical bonds that hold the atoms of each reactant together are first broken so that the atoms may be free to interact with other atoms.
Then a series of collisions with other atoms occur until bond-forming happens. The atoms collide with other atoms of compatible energy and orientation, stick together due to electrostatic attractions, and form bonds. The new substances formed have different properties than the reactants.
To illustrate, the image below shows the formation of water: 2 H₂ molecules react with 1 O₂ molecule forming 2 molecules of H₂O.
The reaction will proceed in this way:
- The bonds within H₂ and O₂ are broken (by absorption of energy).
- Free H atoms and O atoms are now able to intermingle with each other and frequently collide with each other.
- When the atoms of the O and H collide in the proper orientation and when they have the necessary energy requirement, they stick together. H and O atoms form new covalent bonds.
Note that at the start of the reaction here were 4 H atoms and 2 O atoms. This remained the same after the reaction. Two water molecules were formed each having 2 atoms of H and 1 atom of O. Matter was conserved in the reaction.
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Keywords: Law of Conservation of Matter, Chemical Reaction, Products, Reactants