Question

A blacksmith beats up a piece of iron to change its:
A.Physical properties
B.Chemical properties
C.Both A and B
D.None of the above

Answer 1

: We know that changes in a substance can be of two types, namely physical changes and chemical changes. Generally physical changes are reversible changes while chemical changes are irreversible.

Complete answer:
When a blacksmith beats a piece of iron, he does so to alter its shape. The iron piece attains a new physical appearance but the composition and chemical build- up of the substance remains the same. It can also be beat up to obtain the same old shape again. Thus, this change is a physical property of the metal which is known as malleability.
Thus, the correct answer is A.
Note:
We know that changes are of two types. Physical changes are those changes which involve the variation in the state of matter or the shape, size etc. of the substance. It does not involve any change in the composition of the substance and the new substance formed has the same properties as the former. These changes are reversible and the old substance can be obtained back. The melting of ice, folding of paper and elongation of a spring are examples of physical changes involving changes in the state, shape and size of a substance respectively.
On the other hand, chemical changes are those changes which involve a change in the chemical composition of the substance. A new substance is formed as a result of rearrangement of the molecules of the original substance which has different properties and composition. These changes are irreversible and the initial substance cannot be obtained back through simple methods. AN example of a chemical change is the burning of paper or boiling of eggs. The initial paper or raw egg cannot be obtained back after the change has occurred.