Understanding Physical and Chemical Changes

Matter can exist in different forms, and these forms can change. There are two main types of changes that matter can undergo: physical changes and chemical changes. It's important to understand the difference between these two types of changes to better comprehend the behavior of matter.

A physical change is a change in the form or appearance of a substance, but not in its chemical composition. In other words, the substance remains the same, but it may look or feel different. Examples of physical changes include:

• Melting: When a solid turns into a liquid.
• Freezing: When a liquid turns into a solid.
• Boiling: When a liquid turns into a gas.
• Condensation: When a gas turns into a liquid.
• Sublimation: When a solid turns directly into a gas, bypassing the liquid phase.
• Deposition: When a gas turns directly into a solid, bypassing the liquid phase.
• Crushing: When a solid is broken into smaller pieces.
• Dissolving: When a solid, liquid, or gas dissolves in a liquid.

Physical changes are typically reversible. For example, if you melt a piece of ice, you can refreeze it to get your ice back. Similarly, if you dissolve salt in water, you can evaporate the water to get your salt back.

Changing Matter: Understanding Physical And Chemical Changes (My Science Library)

by Tracy Maurer

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Language	:	English
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A chemical change is a change in the chemical composition of a substance. In other words, the substance changes into a new substance with different properties. Examples of chemical changes include:

• Burning: When a substance reacts with oxygen to produce heat and light.
• Rusting: When iron reacts with oxygen and water to form rust.
• Digestion: When food is broken down into smaller molecules by enzymes.
• Photosynthesis: When plants use sunlight to convert carbon dioxide and water into glucose.
• Fermentation: When yeast converts sugar into alcohol and carbon dioxide.

Chemical changes are typically irreversible. For example, if you burn a piece of paper, you cannot unburn it to get your paper back. Similarly, if you rust a piece of iron, you cannot unrust it to get your iron back.

There are a few key ways to tell the difference between physical and chemical changes:

• Physical changes do not produce new substances, while chemical changes do.
• Physical changes are typically reversible, while chemical changes are typically irreversible.
• Physical changes involve changes in the form or appearance of a substance, while chemical changes involve changes in the chemical composition of a substance.

Understanding the difference between physical and chemical changes is important for understanding the behavior of matter. Physical changes involve changes in the form or appearance of a substance, while chemical changes involve the formation of new substances. Physical changes are typically reversible, while chemical changes are typically irreversible.

Changing Matter: Understanding Physical And Chemical Changes (My Science Library)

by Tracy Maurer

4.8 out of 5

Language	:	English
File size	:	4038 KB
Print length	:	24 pages

FREE