Question

What are the characteristics of a chemical change?
A.Permanent
B.Formation of new substances
C.Absorption or release of heat, light
D.All of the above

Answer 1

Chemical changes can be simply understood as the rearrangement of atoms taking place in a chemical reaction, which often result in the formation of different substances, along with the change in the energy state of the system.

Complete Step-by-Step Answer:
Before we move forward with the solution of the given question, let us first understand some important basic concepts.
Chemical changes happen when a substance given chemical substance combines with another substance. This process is called chemical synthesis. On the other hand, chemical changes also take place when a given substance dissociates into two or more substances. This process is known as chemical decomposition. These reactions often include making or breaking of chemical bonds. The resultant products formed are not similar to the reactants because of the formation or breaking of bonds. This can be simply explained by saying that chemical reactions involve the rearrangement of atoms.
When a bond is being formed, the atoms of the substances share electrons and this process releases energy. The magnitude of energy released depends on the shift in stability that takes place from the reactant to the product. Contrarily, breaking of bonds requires energy to be supplied to the system. The amount of energy required is directly dependent on the stability of the bond.
Since chemical changes involve the formation of breaking of chemical bonds, these changes are permanent and can only be reversed by using another suitable chemical reaction.
From the discussion done above, we can say that chemical changes are permanent in nature, result in the formation of new substances, and also involve the absorption or release of energy in the form of heat or light.
Hence, Option D is the correct option

Note: Chemists categorize chemical changes into three main classes: inorganic chemical changes, organic chemical changes and biochemical changes. These categorizations take place depending on the types of reactants that are taken into consideration.