Question

Which of the following are physical changes?
i ) Melting of iron metal.
ii) Rusting of iron.
iii) Bending of an iron rod.
Iv) Drawing a wire of iron metal.
(A)- (i), (ii) and (iii).
(B)- (i), (ii) and (iv).
(C)- (i), (iii) and (iv).
(D)- (ii), (iii) and (iv).

Answer 1

Hint: You might have seen physical changes in your day to day life. They include an ice cube melting into water in your drink, Freezing water to make ice, boiling water known as evaporation.

Complete step by step answer:
Matter makes up everything we can see in the entire universe. Since matter can neither be created nor destroyed, it changes form to cycle throughout the world. In science, physical changes of matter are when the shape, size or smell of it changes, but the chemical properties remain unchanged.Physical changes have a typical impact on the state of matter.
Many physical changes involve the rearrangement of atoms most noticeably in the formation of crystals. Many chemical changes are irreversible, and many physical changes are reversible in nature, but reversibility is not a suitable criterion for classification. Although chemical changes may be recognized by an indication such as smell, color change, or production of a gas, every one of these indicators can result from physical change too.
Now, with reference to the above discussion, let’s check whether the given changes are physical changes or not.
First, we have melting iron metal, in this case the physical structure of iron changes which you might have seen while a blacksmith is doing it’s job but there is no effect on its chemical properties.
Second, we have rusting of iron, you might know that rusting of iron occurs when iron chemically reacts with oxygen in the presence of moisture, therefore it is not a physical change.
In the third case, we have bending of an iron rod. Here, the physical appearance of rod changes but there is no change in his chemical properties, so it is also a physical change.
Finally, we have drawn a wire of iron metal. Drawing is a process of converting metal into thin wires. Here also only the physical characteristic of the metal has changed so it is also a physical change.


Therefore, the correct answer is (C)- (i), (iii) and (iv).


Note: You must have no doubt between a physical and chemical change. Physical change only changes the appearance of a substance and not its chemical properties but in case of chemical change, the substance gets converted into an entirely new one with different chemical properties.