The following Topics and Sub-Topics are covered in this chapter and are available on MSVgo:
Physical and chemical changes are the essential phenomenon of nature that keeps happening all the time around us. You must have heard about energy dissipation in case of chemical changes. There is a fine margin that separates the physical and chemical change, although both can happen simultaneously. For example, the burning of the candle has both physical and chemical deformation. There are different properties of physical and chemical change, which we will discuss below.
Physical changes are the changes that are happening in the physical state of the substance and are temporary. For example, the melting of ice into water is a temporary change. Again, we can get the water to freeze back into ice, melting the ice’s solid shape into the liquid matter. In physical changes, only the physical states of the matter get changed, such as shape, size, volume, etc. Physical change is not associated with the release or absorption of energy.
In some cases, very little energy is absorbed. Also, there are no new substances formed after the physical change. One more factor listed in physical changes is that they are reversible. Hence, we can get the original product back by performing some steps. Another example of physical changes is crystallisation.
During the physical change, the mass is not involved in the change as it remains constant. Only a little energy is added or removed from the substance.
Chemical changes are changes that are happening inside the substance to the atoms and molecules. It is usually not visible in the microscopic parts. Still, we can check them when the change is happening on the macro scale of the substance. Chemical changes are permanent changes and cannot be reversed. For example, in the burning of paper to become ashes, the paper is burnt permanently and is converted into ashes. We cannot bring back paper from the ashes. Chemical changes usually involve the release or absorption of energy. It can be an endothermic or exothermic reaction based on whether the substance absorbs or releases energy upon the chemical change. In a chemical change, we get one or more final products different from the initial product. Like in the case of burning paper, we get ashes. Other examples of chemical change are rusting of iron and the burning of wood.
During a chemical change, the mass of the substance changes as the molecules and atoms changes. A release or absorption of energy breaks the substance’s interatomic and intermolecular bonds.
A chemical change often occurs due to the supply or removal of energy from the system. If you supply more energy to the substance, then the atoms and molecules’ kinetic energy will increase. This will lead to the faster movement of atoms and molecules. When the atoms have sufficient energy absorbed to cross the atom’s threshold energy limit, the atoms move out of the interactive forces and released from the bonds. And hence in this way, there is the degradation of the substances. It is an irreversible reaction where the atoms, once released out of the bond, cannot be recalled until a large amount of energy is again supplied to it. Hence the chemical reactions need the energy to attain a different state and identity.
Many physical and chemical changes are happening all around us. Many differentiating factors separate the physical and chemical changes. For example, the physical changes are reversible, whereas the chemical changes are irreversible. There are many examples of physical change, such as crystallisation, dissolution of sugar in water, water boiling, and more. Also, there are many examples of chemical changes, such as rusting, burning paper, milk souring, and more.
On the MSVgo app, you can check-in details about the major differentiating factors between the physical and chemical change. You can also find many different examples of both physical and chemical changes.