In our daily life, we encounter many changes in our surroundings, though we do not notice them, such as souring of milk, rusting of iron, stretching of a rubber band, bread becoming toast, melting of wax, liting of a match, etc. All these changes that take place around us are physical change or chemical change. Physical changes are the changes that change the physical traits of the substance, without making any change in their internal structure. On the other hand, a chemical change is one that affects the internal structure of the substance, so as to form a new substance. So, take a read of the article to understand the difference between physical change and chemical change.
Content: Physical Change Vs Chemical Change
- Comparison Chart
- Key Differences
- Example of both changes occuring simultaneously
|Basis for Comparison||Physical Change||Chemical Change|
|Meaning||Physical change refers to a change in which the molecules are rearranged but their internal composition remains same.||Chemical Change is a process in which the substance transforms into a new substance, having different chemical composition.|
|Example||Tearing of paper, melting/freezing of water, cutting of trees, etc.||Burning of wood/trees/paper, rusting of iron, setting of curd, etc.|
|Original matter||Can be recovered||Cannot be recovered|
|Involves||Change in physical properties of the substance, i.e. shape, size, color etc.||Change in chemical properties and composition of the substance.|
|Product Formation||No new product is formed.||New product is formed.|
|Energy||Absorption and evolution of energy do not take place.||Absorption and evolution of energy take place, during reaction.|
Definition of Physical Change
Physical change is a process in which the substance experiences change in its physical properties like shape, size, colour, volume, appearance, state (i.e. solid, liquid, gas), etc., that, without making any change in their molecular composition. These changes are volatile in; that can be reversed using simple physical methods.
The same element or compound exists prior, or after change, i.e. original characteristics of the object remain unchanged. For example, Melting of wax, boiling of water, dissolving sugar in water, chopping wood, crumpling of paper, etc.
Definition of Chemical Change
Chemical Change is defined as the process in which the atoms of one or more substances are rearranged or combined to form a new substance. When a substance undergoes chemical change, the chemical properties of the substance changes and it is transformed into a different substance with different chemical composition. Evolution of energy, the formation of bubbles, change in odour, change in temperature are some signs of chemical change.
Alternately, known as chemical reaction, wherein the substances involved are known as reactants, and the outcome of the reaction is called product. Energy change is one of the characteristics of a chemical change, because of the formation of the new product. Once the chemical change takes place, it cannot be reversed. For example, adding vinegar to baking soda, bleaching a stain, fermenting of grapes, etc.
Key Differences Between Physical Change and Chemical Change
The points given below discusses significant differences between physical change and chemical change
- A change in which the molecules are rearranged, but their internal composition remains same is called Physical Change. A process in which the substance transforms into a new substance, having a different chemical composition, it is known as Chemical Change.
- Some common examples of physical change vaporisation, condensation, freezing/melting/boiling of water. On the contrary, the examples of chemical change are combustion, metabolism, cooking of egg, etc.
- Physical change is a temporary; they are easily reversible. As against this, the chemical change is permanent in nature, i.e. they cannot be reversed, even by reversing conditions.
- In the physical change, only the form of the substance is changed, but no new product is formed. On the other hand, when there is a chemical reaction, a completely different product is formed, whose properties are completely different from that of the reacting substances.
- In a physical change, the original matter can be recovered, by simple physical methods. As opposed, in chemical change the original matter no longer exist, and so it cannot be recovered.
- In the physical change, change in the physical attributes of the substance is observed, such as shape, size, appearance, texture, odour, density and so on. Conversely, chemical change involves the change in chemical properties of the substance, i.e. change in its chemical nature.
- In the physical change, no or very little amount of energy is absorbed or given out as heat, light or sound energy. Unlike chemical change, wherein enormous energy is absorbed or given out as heat, light or sound energy
Example of both changes occuring simultaneously
- Burning of candle: While melting of wax is a physical change, as the state of the substance changes from solid to liquid, burning of wax is a chemical change, as after consuming energy from wax, light lits up.
- Cooking of food: Cooking of raw vegetables or grains is a chemical change and transformation of water into steam is a physical change.
To sum up, physical change is any change that only transforms the substance’s physical properties, but chemical change results in the change in the chemical structure of the substances involved.