Physical and Chemical Changes Explanation at Embibe
  • Written By Sumana_C
  • Last Modified 05-07-2022
  • Written By Sumana_C
  • Last Modified 05-07-2022

Physical and Chemical Changes: Detailed Explanation

Physical and Chemical Changes: Physical and chemical changes differ significantly from one another, and students who want to comprehend these ideas thoroughly must be aware of these differences to score well on the exam. 

Every day we encounter many changes in our surroundings. These changes can have one or more substances. Let us understand this with an example. If you dissolve sugar in water to make a cold drink, you are creating a change by making a sugar solution. Similarly, setting curd from milk is also a change, and souring milk is another change. If you stretch a rubber band, it also represents a change.

Below are instances of the similarities and contrasts between physical and chemical changes. It is critical to understand the definitions of physical and chemical properties and their changes. For additional information on these changes in detail, visit physical and chemical alterations. Students can check the contrasts between physical and chemical changes in the below table.

The Difference Between Physical and Chemical Changes

Check out the primary differences between physical and chemical changes.

Physical ChangeChemical Change
When a substance undergoes a physical change, the makeup of a substance changes physically, but the arrangement of its molecules does not change.A substance’s molecular structure completely changes as it goes through a chemical transformation. Therefore, new compounds are created as a result of chemical reactions.
A transient change is a physical one.A permanent change is a chemical alteration.
Only physical properties, such as shape, size, etc., are impacted by physical change. The chemical change affects the substance’s both physical and chemical properties, including its composition
There is almost no or very little energy absorbed during a physical change.Energy is both absorbed and evolved during a chemical reaction.
The freezing of water, boiling of water, melting of wax, etc., are some examples of physical change.Several instances of chemical transformation include the burning of coal, digestion of food, rusting, etc.
Generally, physical changes do not produce energy.Chemical changes usually produce energy (It can be in the form of sound, light, heat, etc.)
No new substance comes into existence in a physical change.A chemical change always comes up with one or more new substance(s).
Physical change is reversible. It means the original substance can be recovered.Chemical changes are not reversible. It means the original substance cannot be recovered.

Students must have understood the primary difference between chemical and physical changes. The primary difference is physical changes are reversible. On the other hand, chemical changes are usually not. To learn more about the difference between physical and chemical changes, check some of the detailed examples below.

Chemical Changes Examples

A chemical change happens when the atoms rearrange themselves to form new chemical bonds, creating a new compound (product). Chemical reactions are always a part of chemical changes. The initial components and the finished product differ chemically from one another. Here are a few instances of chemical modifications:

  • Burning wood
  • Mixing acid and base
  • Souring milk
  • Digesting food
  • Heating sugar to form a caramel
  • Cooking an egg
  • Rusting of iron
  • Baking a cake

Physical Changes Examples

In a physical transformation, no new chemical species is created. The identity of the matter does not change when a pure material transit between the solid, liquid, and gas phases. Students can easily understand that the shift is a physical change.

  • Melting an ice cube
  • Crumpling a sheet of aluminium foil
  • Casting silver in a mould
  • Boiling water
  • Breaking a bottle
  • Evaporating alcohol
  • Dry ice sublimation into carbon dioxide vapour
  • Shredding paper
  • Carbon transforming from graphite into a diamond

How to Find Out Physical or Chemical Change?

If you want to find out whether it is a physical or a chemical change, look for an indication. When does a chemical change occur? Check out the signs of a chemical change below.

  • Gas is produced. 
  • An odour is produced.
  • Bubbles may form in liquids.
  • The substance changes color.
  • In a temperature change, the surroundings become either cold or hot.
  • Sound is produced.
  • A precipitate forms.
  • Light is produced.
  • The change is hard or possible to reverse.

All of these indications of a chemical alteration might not be present. If none of these symptoms is present, a bodily change most likely took place. Be mindful that a substance’s appearance can drastically change in response to a physical change. A physical change has the ability to produce every physical change indicator. This is not proof that a chemical reaction took place. Chemical analysis of the starting and ending components is the only approach to conclusively determine whether a change is chemical or physical.

Sometimes it would not be obvious if a change was chemical or physical. The physical change that occurs when sugar dissolves in water is an illustration. The sugar’s structure changes, but its chemical makeup remains the same (sucrose molecules). When salt dissolves in water, though, it undergoes a chemical change because the salt splits into its ions (from NaCl into Na+ and Cl-). In both instances, a white solid dissolves into a clear liquid, and in both instances, you can regain the original substance by skipping the water, but the methods are different. 

Key Takeaways: Chemical and Physical Change Examples

Let us look at the examples of chemical and physical change.

  • While a physical change happens when matter changes forms without changing its chemical identity, a chemical change is the ultimate result of a chemical reaction.
  • Burning, frying, rusting, and rotting are a few instances of chemical transformations.
  • Boiling, melting, freezing, and shredding are a few examples of physical transformations.
  • If enough energy is provided, many physical changes can be reversed. A different chemical reaction is the only way to undo a chemical change.

Frequently Asked Questions – FAQs on Physical and Chemical Changes

Check out the frequently asked questions on physical and chemical changes.

Q.1 How do you distinguish between chemical and physical changes?

Ans: During a physical change, matter’s shape or appearance changes, but the substance’s composition does not. Contrarily, a chemical shift causes the development of at least one new compound with novel properties.

Q.2 Why is it crucial to understand the distinction between chemical and physical changes?

Ans: Understanding the distinction between chemical and physical changes is crucial. Although there are many evident changes, there are some essential ideas, and students must be aware of them. Physical alterations typically relate to modifications to an object’s physical state. Chemical changes take place at the molecular level when two or more molecules interact.

Q.3 Give us some examples of physical and chemical changes.

Ans: The processes of burning, frying, rusting, and rotting are examples of chemical changes. Examples of physical changes are melting, freezing, boiling, and shredding. If enough energy is available, the majority of physical changes can be reversed. Only a different chemical reaction can undo a chemical change.

Q.4 How can you tell if the shift is chemical or physical?

Ans: Look for signs that a chemical change has occurred. The signs of a chemical alteration include:

  • A gas is produced. 
  • Liquids can contain bubbles.
  • A smell is produced.
  • The substance’s colour changes.
  • Sound is produced.
  • The temperature is fluctuating. Either the climate warms up or cools down.
  • Light is produced.
  • Precipitation forms.
  • Reversing the change is difficult or impossible.

Q.5 Which three forces have the power to alter the physical world?

Ans: Physical changes can be caused by forces like motion, temperature, and pressure. The chemical links between sugar and oxygen in the air are destroyed because oxygen in the air reacts with sugar.

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