Difference Between Physical and Chemical Change

Physical and Chemical change are the two major classifications of change that occur in various components present in the surrounding. The significant difference between physical and chemical change is that a physical change is a type of change that affects the physical properties of the materials. On the contrary, a chemical change is a type of change where the actual variation is noticed in the chemical composition of the substance.

Basically, change corresponds to the variation in the properties of the material either physically or chemically. We all are aware of the fact that various changes occur in our day to day life in our surrounding. These changes can be rusting of iron, burning of wood, stretching of rudder band, freezing of water, etc.

When we talk about change in our day-to-day life then sometimes change is only associated with the physical appearance of the material while sometimes it is related to the change in chemical composition. When a change occurs in the physical context then no new substance is produced as only its appearance changes. While when a change is noticed in a chemical composition then it definitely leads to produce a new substance.

Here in this content, we will see on what factors a physical change is differentiated from a chemical change.

Content: Physical Change Vs Chemical Change

  1. Comparison Chart
  2. Definition
  3. Key Differences
  4. Conclusion

Comparison Chart

Basis for ComparisonPhysical ChangeChemical Change
BasicOriginal composition of the material is not changed.Complete change in chemical composition of the material.
NatureTemporaryPermanent
Noticeable variationIn shape, size, colour, etc. of the material.Majorly chemical composition of the material changes that resultantly varies the physical characteristics.
ReversibilityGenerally existGenerally do not exist
Energy absorptionAlmost negligible or very small amount of energy is absorbed.The chemical change is the result of energy absorption in specific amount.
Energy productionEnergy is not produced.Some amount of energy is produced in the form of heat, light, etc.
New substanceNot formedNecessarily produces one or even more substances.
ExampleBending of wireRusting of iron

Definition of Physical Change

A type of change that is associated with variation in the physical property of a substance rather than its chemical composition is known as physical change. The properties of the substance altered during physical change are odour, rigidity, solubility, colour, temperature, size, shape, melting point, boiling point, texture, etc.

This change generally affects the form of chemical substance rather than affecting its chemical composition.

Now, the question arises, how the form can be changed without the change in chemical composition.

So basically, sometimes a physical change is such that the molecular orientation changes that automatically vary the form of the substance without causing a change in chemical composition.

Some examples of physical changes are as follows:

  • Freezing of water
  • Fading of the colour of clothes
  • Bending of wire
  • Cutting of wood
  • Melting of ice

Definition of Chemical Change

A type of change that varies the chemical composition of the substance along with the change in physical properties is known as chemical change or chemical reaction. Basically, as the chemical change is associated with a change in the composition of the substance thus this leads to providing a generation of one or more substances.

When the composition of the substance changes then as the actual substance gets changed thus the generated product sometimes may possess different physical characteristics as well. On a general basis, it is said that a chemical change brings out a change in the physical characteristics of the substance.

Some examples of chemical changes are:

  • Burning of wood
  • Food souring
  • Mixing of salt and water
  • Decomposing of waste
  • Photosynthesis

Key Differences Between Physical and Chemical Change

  1. The key factor of differentiation between physical and chemical change exists on the basis of change in the composition of the substance. A physical change never results in varying in the chemical composition of the substance as only the physical properties of the substance changes. As against, a chemical change necessarily brings out variation in the chemical composition of the substance thereby resulting in a new composition from the original one.
  2. Physical changes are of reversible nature and so when a physical change occurs then it is possible to get back to the original state. While chemical changes are irreversible changes which can never be brought back to the original composition.
  3. As physical changes show reversible behaviour thus these are temporary. But due to irreversible behaviour, chemical changes are truly permanent.
  4. When a physical change occurs then it causes variation in the shape, size, and colour of the substance. However, when a chemical change occurs then the actual variation occurs in the chemical composition of the substance and this automatically changes the physical properties associated with the original substance.
  5. In the case of physical change, no new substance is generated as the only variation occurs in physical appearance. On the contrary, a chemical change necessarily generates one or even more substances due to a change in the chemical composition.
  6. For a physical change to take place no significant amount of energy is required as its occurrence needs a very small amount of energy that can be taken from the surrounding. While for a chemical change to take place a significant amount of energy is required so that the variation in chemical composition occurs.
  7. A physical change never produces energy but a chemical reaction when occurs gives off energy in the form of heat, light, etc.

Conclusion

So, this discussion concludes that physical and chemical changes are classified on the basis of the result according to the occurred action. When the change results in the variation of appearance like the change of state of ice on melting then it is called a physical change. As against, when a change causes variation in chemical composition along with its appearance like rusting of iron then it is known as chemical change.

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