Write “P” for physical change and “C” for chemical change in the following:
(a) Dissolving salt in water
(b) Freezing of water.
(c) Rusting of iron.
(d) Frying an egg.
(e) Heating ice to form water.
(f) Digestion of food.
Write “P” for physical change and “C” for chemical change in the following:
(a) Dissolving salt in water
(b) Freezing of water.
(c) Rusting of iron.
(d) Frying an egg.
(e) Heating ice to form water.
(f) Digestion of food.
Chemical change: A change in which new substances are formed is known as chemical change.
Physical change: The change in which the physical properties of a substance change but no new substance is formed is known as a physical change.
Examples of physical and chemical change:
(a) Dissolving salt in water - P
When we dissolve salt in the water we see that only the appearance of the solution changes but there is no new substance produced. Hence, it is a physical change.
(b) Freezing of water - P
When water is frozen it turns solid, i.e, a change in appearance and state. Hence, it is a physical change.
(c) Rusting of iron - C
- Iron rusts when it comes in contact with air and water.
- This is because there is a formation of an oxide of iron.
- Since a new substance is formed it is a chemical change.
(d) Frying an egg - C
When we fry an egg, the liquid component of the egg changes from solid to liquid. Hence, it is a chemical change.
(e) Heating ice to form water - P
- When we heat ice, it starts melting and converts into water.
- There is no change in the property of ice nor there is any new substance formed. Hence, it is a physical change.
(f) Digestion of food - C
When food is ingested it is acted upon by starch and on reaching the stomach a lot many enzymes act upon it, after which a new substance is formed. Hence, it is a chemical change.
Chemical change: A change in which new substances are formed is known as chemical change.
Physical change: The change in which the physical properties of a substance change but no new substance is formed is known as a physical change.
Examples of physical and chemical change:
(a) Dissolving salt in water - P
When we dissolve salt in the water we see that only the appearance of the solution changes but there is no new substance produced. Hence, it is a physical change.
(b) Freezing of water - P
When water is frozen it turns solid, i.e, a change in appearance and state. Hence, it is a physical change.
(c) Rusting of iron - C
- Iron rusts when it comes in contact with air and water.
- This is because there is a formation of an oxide of iron.
- Since a new substance is formed it is a chemical change.
(d) Frying an egg - C
When we fry an egg, the liquid component of the egg changes from solid to liquid. Hence, it is a chemical change.
(e) Heating ice to form water - P
- When we heat ice, it starts melting and converts into water.
- There is no change in the property of ice nor there is any new substance formed. Hence, it is a physical change.
(f) Digestion of food - C
When food is ingested it is acted upon by starch and on reaching the stomach a lot many enzymes act upon it, after which a new substance is formed. Hence, it is a chemical change.
