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Physical Chemical Changes

Last updated date: 19th Jun 2024
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We see different types of physical and chemical changes in our surroundings like dissolving sugar and water, burning of coal, rusting, melting an ice cube, boiling water, different shape and size of the Moon, etc., change is occurring all around us every time. Have you ever tried to understand these changes? We should try to understand the terms that are physical and chemical changes and examples, reversible and irreversible changes before knowing the scientific reason for changes. There are many reasons for these physical and chemical changes. We will understand more about this by starting with the physical change definition.

What is a Physical Change?

Properties such as shape, size, volume, colour, appearance, and state of a substance (solid, liquid, and gas) are called physical properties. A change in which a substance undergoes a change in its physical properties is termed physical change.  Physical changes only change the appearance of a substance, not the chemical composition. Examples of physical changes: boiling water, breaking a glass, melting an ice cube, freezing water, mixing sand and water, crumpling of paper, and melting a sugar cube.

Physical changes are the changes that influence the type of a synthetic substance, yet not its compound creation. Physical changes are utilized to isolate blends into their part compounds yet can not typically be utilized to isolate compounds into synthetic components.

Physical changes happen when articles or substances go through a change that doesn't change their compound creation. This differentiates with the idea of synthetic change wherein the structure of a substance changes or at least one substance consolidates or separated to shape new substances. Overall a physical change is reversible utilizing physical means. For instance, salt dissolved in water can be recuperated by permitting the water to vanish.

A physical change includes a change in physical properties. Instances of physical properties incorporate softening, progress to a gas, change of solidarity, change of sturdiness, changes to gem structure, textural change, shape, size, shading, volume, and thickness.

An illustration of a physical change is the most common way of treating steel to frame a blade sharp edge. A steel clear is over and again warmed and pounded which changes the hardness of the steel, its adaptability, and its capacity to keep a sharp edge.

Numerous physical changes additionally include the adjustment of molecules most discernibly in the development of precious stones. Numerous substance changes are irreversible, and numerous physical changes are reversible; however, reversibility is anything but a specific standard for order. Albeit compound changes might be perceived by a sign, for example, scent, shading change, or creation of gas, all of these pointers can result from the physical change.

What is a Chemical Change?

A chemical change is said to happen when one chemical substance is transformed into one or more different substances, or chemical changes happen when a substance consolidates with one or more to shape another substance, called the chemical union, or, on the other hand, chemical decay into at least two distinct substances. These cycles are called chemical responses and, by and large, are not reversible besides by additional chemical responses. A few responses produce heat and are called exothermic responses.

At the point when chemical responses occur, the molecules are modified and the response is joined by an energy change as new items are produced. An illustration of a chemical change is the response between sodium and water to create sodium hydroxide and hydrogen. Such a lot of energy is delivered that the hydrogen gas delivered suddenly consumes in the air. This is an illustration of a chemical change on the grounds that the finished results are chemically not quite the same as the substances before the chemical response. Chemical changes occur by the process of chemical reactions, and the resulting substances have different properties because their atoms and molecules are arranged differently. Examples of chemical changes: rusting of iron, burning of coal, digestion of food, germination of seeds, adding vinegar to baking soda, ripening of fruits, fermenting of grapes, cooking an egg, etc.

The below table shows the major differences between physical and chemical change.

Difference Between Physical Change and Chemical Change

Physical Changes

Chemical Changes

No new substance formed in a physical change.

In a chemical change, a new substance is formed.

Change in physical property occurs.

Change in physical and chemical properties occurs.

It is a reversible process.

It is an irreversible process.

It is a temporary change.

It is a permanent change.

In a physical change, no energy is generated.

In a chemical change, energy is generated in the form of heat, sound, light, etc.

For example, shredding paper, boiling water, breaking a glass, chopping wood, crumpling of paper, and melting a sugar cube.

For example, burning of coal, digestion of food, germination of seeds, cooking an egg, adding vinegar to baking soda, and fermenting of grapes.

Fun Facts 

  • Bending of metal is considered a physical change but corrosion of metal is a chemical change.

  • Melting and burning of candle wax are considered both physical and chemical changes.

FAQs on Physical Chemical Changes

1. What are reversible change and irreversible change?

Reversible Change: Reversible changes are those changes that can be reversed. For example, condensation, boiling, evaporation, freezing, melting, and dissolution are reversible changes.

Irreversible Changes:  Irreversible changes are those changes that cannot be reversed. For example, cooking food, fermenting grapes, and turning milk into cheese.

2. What defines a chemical change?

The changes in which new substances with new chemical properties are formed can be termed chemical changes. It takes place on the molecular level. For example, germination of seeds, adding vinegar to baking soda, fermenting of grapes, rusting of Iron, and cooking an egg.

Chemical changes include the formation of a precipitate, change in colour, change in temperature (increase or decrease), change in volume, and evolution of energy.

3. Give an example of physical change that occurs by the action of heat?

Melting ice to form water is a physical change that occurs by the action of heat.

4. Is the souring of milk physical or chemical change?

Souring of milk will come under chemical change because the original substance present in milk loses its nature and forms new chemical substances.