I. a chemical change breaks bonds, forms new substances, and is irreversible.

ii. reordering the intermolecular forces is indicative of a chemical change.

iii. during a physical change the substance remains the same, no bonds are broken, and the process is reversible.

iv. permanently altering the makeup of the substance is characteristic of a physical change.

which conclusion(s) best elaborate(s) on the difference(s) between a chemical change and a physical change?
a) i & iii
b) ii & iv
c) iii & ii
d) iv & i

Option (A) is the correct answer.

Explanation:

Chemical changes are defined as the change which tend to show difference in chemical composition of a substance.

For example, toxicity, reactivity, combustion etc are all chemical properties.

A chemical change will always lead to the formation of a new compound and this change is irreversible in nature by any physical means.

On the other hand, a change which is unable to bring any difference in chemical composition of a substance is known as a physical change.

For example, change in shape, size, mass, volume etc are all physical properties.

Physical changes are reversible in nature.

Therefore, we can conclude that given conclusions which best elaborate on the difference between a chemical change and a physical change are as follows.

I. A chemical change breaks bonds, forms new substances, and is irreversible.

III. During a physical change the substance remains the same, no bonds are broken, and the process is reversible.

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