Melting, freezing, and evaporation are example of physical change. true or false
The correct answer and explanation is:
True.
Melting, freezing, and evaporation are all examples of physical changes. A physical change refers to a transformation in which a substance changes its form or state but its chemical composition remains unchanged.
Melting occurs when a solid turns into a liquid as heat is added. For example, ice melts into water. During this change, the molecules in the solid begin to move faster, breaking the bonds that hold them in place, but the molecular structure of the substance (water in this case) remains the same.
Freezing, on the other hand, is the opposite of melting. It occurs when a liquid turns into a solid as heat is removed. When water freezes, its molecules slow down and form a more structured arrangement, turning into ice. Again, the chemical structure of the water does not change.
Evaporation is the process by which a liquid turns into a gas, usually when it is heated. For example, when water boils, it changes from a liquid to steam, which is a gas. The individual water molecules move faster as heat is added, and they escape the liquid phase to become gas. Even though the physical state of the water changes, its molecular makeup remains the same.
These are all examples of phase changes, which are physical changes because they involve a change in the state of matter (solid, liquid, or gas) without altering the substance’s chemical composition. During physical changes, the molecules or atoms of the substance are not rearranged into new substances. The change is usually reversible, meaning the substance can return to its original state under appropriate conditions.