Which of the following is a physical change and which is a chemical change? Explain
(i) Wool being knitted into a sweater
(ii) Coal being burnt in air
(iii) Melting of butter in a pan
(iv) Cutting of trees
(v) Dissolving of sugar in water
Which of the following is a physical change and which is a chemical change? Explain
(i) Wool being knitted into a sweater
(ii) Coal being burnt in air
(iii) Melting of butter in a pan
(iv) Cutting of trees
(v) Dissolving of sugar in water
Changes of matter can be classified into two. physical and chemical changes
Physical changes Chemical changes Changes which involve only physical properties like colour, appearence etc.., Changes which involve chemical properties like bonding, energy etc.., No new substances are formed Generally new substances are formed It doesn't involve with enery, heat change It does involve with energy, heat change
By analysing the properties of physical, chemical changes we can classify:
(i) Wool being knitted into a sweater is a physical change
Since it involve only change in appearance.
No new substances are formed here.
The chemical properties of the substance doesn't change
(ii) Coal being burnt in air is a chemical change
Burning of coal produces new substances like carbon dioxide
Chemical properties of the substance changed.
(iii) Melting of butter in a pan is a physical change
During melting, the state of change occur.
The chemical properties, composition doesn't change.
We can get the initial product (butter) by cooling it.
(iv) Cutting of trees is a physical change
No new substances are formed here
Only shape, and size got changed here i.e., physical properties.
(v) Dissolving of sugar in water is a physical change
No new substances are formed here.
We can get the initial product (sugar) from the solution by evaporation method
Physical changes:
(i) Wool being knitted into a sweater is a physical change
(iii) Melting of butter in a pan is a physical change
(iv) Cutting of trees is a physical change
(v) Dissolving of sugar in water is a physical change
Chemical changes:
(ii) Coal being burnt in air is a chemical change
Changes of matter can be classified into two. physical and chemical changes
| Physical changes | Chemical changes |
| Changes which involve only physical properties like colour, appearence etc.., | Changes which involve chemical properties like bonding, energy etc.., |
| No new substances are formed | Generally new substances are formed |
| It doesn't involve with enery, heat change | It does involve with energy, heat change |
By analysing the properties of physical, chemical changes we can classify:
(i) Wool being knitted into a sweater is a physical change
Since it involve only change in appearance.
No new substances are formed here.
The chemical properties of the substance doesn't change
(ii) Coal being burnt in air is a chemical change
Burning of coal produces new substances like carbon dioxide
Chemical properties of the substance changed.
(iii) Melting of butter in a pan is a physical change
During melting, the state of change occur.
The chemical properties, composition doesn't change.
We can get the initial product (butter) by cooling it.
(iv) Cutting of trees is a physical change
No new substances are formed here
Only shape, and size got changed here i.e., physical properties.
(v) Dissolving of sugar in water is a physical change
No new substances are formed here.
We can get the initial product (sugar) from the solution by evaporation method
Physical changes:
(i) Wool being knitted into a sweater is a physical change
(iii) Melting of butter in a pan is a physical change
(iv) Cutting of trees is a physical change
(v) Dissolving of sugar in water is a physical change
Chemical changes:
(ii) Coal being burnt in air is a chemical change
