Classify the following as a physical or a chemical change :
(a) Drying of wet clothes
(b) Manufacture of salt from seawater.
(c) Butter getting rancid
(d) Boiling of water
(e) Burning of paper
(f) Melting of wax
(g) Burning of coal
Classify the following as a physical or a chemical change :
(a) Drying of wet clothes
(b) Manufacture of salt from seawater.
(c) Butter getting rancid
(d) Boiling of water
(e) Burning of paper
(f) Melting of wax
(g) Burning of coal
Physical change
(a) Drying of wet clothes - It does not cause any change in chemical composition and no new product is formed hence it is a physical change.
(b) Manufacture of salt from seawater - There is no change in chemical composition after evaporation of sea water to obtain the salt hence it is a physical change.
(d) Boiling of water - It does not lead to any change in chemical composition of water and water after boiling converts to vapor which has same chemical composition as that of water, hence it is a physical change.
(f) Melting of wax - No new products are formed and the chemical composition remains same , hence it is a physical change.
(h) Formation of clouds - Here only phase transformation takes place from water to gas during water cycle and then gas to liquid , hence only state is changed not the chemical composition thus it is a physical change.
(i) Making of a sugar solution - Since after dissolution the composition of sugar and water remains same and also both of the contents can be regained back by the process of vaporization hence it is a physical change.
(j) Glowing of an electric bulb - Since no new products are formed hence it is a physical change
Chemical change
(c) Butter getting rancid - Here oxidation reaction is being undergone and new product is formed , hence it is chemical change.
(e) Burning of paper - Since it leads to a chemical process of combustion and a new product named ash is formed , thus it is chemical change.
(g) Burning of coal - Since this leads to conversion of carbon to carbon dioxide and the process cannot be reversed hence it is a chemical change.
(k) Curdling of milk - Since this process undergoes coagulation to form curd which cannot be reversed back hence it is a chemical change.
Physical change
(a) Drying of wet clothes - It does not cause any change in chemical composition and no new product is formed hence it is a physical change.
(b) Manufacture of salt from seawater - There is no change in chemical composition after evaporation of sea water to obtain the salt hence it is a physical change.
(d) Boiling of water - It does not lead to any change in chemical composition of water and water after boiling converts to vapor which has same chemical composition as that of water, hence it is a physical change.
(f) Melting of wax - No new products are formed and the chemical composition remains same , hence it is a physical change.
(h) Formation of clouds - Here only phase transformation takes place from water to gas during water cycle and then gas to liquid , hence only state is changed not the chemical composition thus it is a physical change.
(i) Making of a sugar solution - Since after dissolution the composition of sugar and water remains same and also both of the contents can be regained back by the process of vaporization hence it is a physical change.
(j) Glowing of an electric bulb - Since no new products are formed hence it is a physical change
Chemical change
(c) Butter getting rancid - Here oxidation reaction is being undergone and new product is formed , hence it is chemical change.
(e) Burning of paper - Since it leads to a chemical process of combustion and a new product named ash is formed , thus it is chemical change.
(g) Burning of coal - Since this leads to conversion of carbon to carbon dioxide and the process cannot be reversed hence it is a chemical change.
(k) Curdling of milk - Since this process undergoes coagulation to form curd which cannot be reversed back hence it is a chemical change.
