(i) occurrence of day and night, growth of plant & animal body
(ii)No, because it is an irreversible change
(iii)Because no new substance is formed
(iv)It is a man-made, reversible & physical change.
(v) melting of wax
Baking of bread
(i)Physical
(ii)Physical
(iii)Chemical
(iv)Physical
(v)Physical
(i)It is an act or process through which something becomes different.
(ii)An exothermic reaction is a chemical reaction that releases energy through light or heat.
(iii)The process of turning from liquid into vapour is called Evaporation
(iv)Expansion is defined as increase in volume of a substance resulting from increase in temperature.
(v)Condensation is the process by which water vapor in the air is changed into liquid water.
(i)A change which can be reversed to form the original substance by reversing the conditions that caused it, is called reversible change
E.g. – freezing of water into ice
Melting of wax
(ii)No she won’t be successful.
When POP is mixed with water then an irreversible chemical change takes place and a new substance is formed. When the vase is converter into dust it is an irreversible physical change. when the dust is mixed with water no chemical change will take place to solidify.
(iii)
Physical change |
Chemical changes |
The composition of the molecules remains same. |
There is complete change of molecules. |
No energy is generated |
Energy is generated |
(i)The name of the process is evaporation
(ii)Evaporation – The process of turning liquid into vapour is called evaporation.
(iii)Condensation
(iv)If water is kept below 0o C then it will freeze to ice.
(i)This picture shows rusted iron chain in the left and non-rusted shining iron chain in the right.
(ii)When the shining iron chain comes in contact with oxygen and moisture for long time , then a chemical change occurs on its surface and forms a layer of rust.
(iii)It is a type of irreversible chemical change.
(i)Figure A is non -periodic change. It is non-periodic because it doesn’t occur after a specific time interval.
(ii)Water freezing into ice,
Beating of heart
(iii)Changing phases of moon/change of season/clock striking an hour.
(i)The above picture shows a wooden wheel and a metal rim.
(ii)The size or diameter of the metal rim is always smaller than the size of the wooden wheel.
(iii)Expansion and contraction
(iv)After heating the rim, the rim expands, once the rim is put around the wheel, then cold water is given on it. The cold-water cools down the metal rim and hence brings about a contraction & makes it tightly fit on the wheel.