Question

Expansion on heating and contraction on cooling of metals is a:
A) chemical change B) physical change C) irreversible change D) None of these

Answer 1

Physical Change

Explanation:

Physical change is a change that happens and come back to its original form without creating any new substance.

Answer 2

Expansion on heating and contraction on the cooling of metals is a B) physical change

About Physical change:

• Physical modifications are those that modify a chemical substance's shape but not its chemical content.
• Physical changes may normally be used to separate compounds into chemical elements or simpler compounds, but they cannot be used to separate mixtures into their component components.
• Examples of physical change include changes in the composition or size of materials.
• Transitions between states, such as from a solid to a liquid or a liquid to a gas, are examples of physical transformations.
• Some of the processes that result in physical changes include cutting, bending, dissolving, freezing, boiling, and melting.

About Chemical change:

• Chemical synthesis, or, alternatively, chemical breakdown into two or more separate molecules, occurs when one material reacts with another to create a new substance.
• These processes are referred to as chemical reactions, and they are often irreversible barring additional chemical reactions.
• The energy changes happen when a chemical reaction takes place.
• There is a difference in energy between the creation of new bonds in products and the breaking of existing bonds in reactants.

About irreversible changes:

• Reversible changes can be undone, but irreversible changes are permanent.
• Reactants generate a completely new chemical by a reaction that cannot be stopped.
• A few operations that result in permanent alterations are heating, burning, combining, and powdering.

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