Question

a) Classify the given examples into physical and chemical changes. Digestion of food , Melting of butter , Crushing of aluminium foil, Photosynthesis in plants​

Answer 1

Answer:

digestion - chemical

melting of butter - physical

crushing of aluminium foil - physical

photosynthesis- chemical

Answer 2

Physical changes only lead to changes in physical properties of the substance and are reversible chemical changes lead to change in composition or the structure and are irreversible in nature.
(a) Photosynthesis: irreversible, chemical changes.
6CO
2
​
+6H
2
​
O⟶C
6
​
H
12
​
O
6
​
+6O
2
​

(b) Dissolving of water : reversible, physical change.
(c) Bumping of coal − irreversible, chemical change.
(d) Melting of wax − reversible by cooling, physical change.
(e) Physical change as mallacbility (beating metal into then sheets) does not change composition.
(f) Digestion − chemical change.