Question

Differentiate between irreversible physical change and reversible physical change
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Answer 1

Explanation:

All changes in the world are one of the two types – Reversible changes and irreversible changes. A change which can happen backward, that is, can be reversed is called a reversible change. If you keep water in the freezer for some time, it transforms into ice. But as soon as you take it out of the freezer, it turns into water again. This is a reversible change. Similarly, if you boil water, it evaporates and becomes water vapor. When you cool this vapor down, it turns back to water

A change which cannot happen backward, that is, it cannot be reversed is called an irreversible change. When you burn a piece of paper, it turns to ash. It cannot become paper again. Your height cannot decrease. These are irreversible changes. They cannot be reversed at all.

1. Reversible changes

• A substance can return to its original state.
• The chemical properties of the substance do not change.
• Most physical changes are reversible changes.

2. Irreversible changes

• A substance cannot return to its original state.
• The chemical properties of the substance change.
• All chemical changes are irreversible changes.

Answer 2

In reversible change the change can be reversible and in irreversible change it cannot reverse. Two or more new substance can be formed in the irreversible change . No substance can be formed in the reversible change . Eg:- of reversible change is dissolving sugar in water , formation of ice . Eg of irreversible change squeezing of lemon , photosynthesis , digestion etc