Physical and Chemical Changes

Front

What is a physical change?

Back

A physical change is a change that affects one or more physical properties of a substance without altering its chemical composition. Examples include melting ice, boiling water, and dissolving sugar in water.

Front

What is a chemical change?

Back

A chemical change is a change that results in the formation of new chemical substances. It involves a chemical reaction and includes changes such as rusting, burning, and baking.

Front

What evidence indicates a chemical change has occurred?

Back

Evidence of a chemical change includes color change, gas production (bubbles), temperature change, and the formation of a precipitate (solid).

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Can physical changes be reversed?

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Yes, physical changes can often be reversed. For example, ice can melt into water and then freeze back into ice.

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Can chemical changes be reversed?

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Chemical changes are usually not reversible by simple physical means. For example, burning wood creates ash and gases, which cannot be turned back into wood.

Front

What happens to the particles in a substance during a physical change?

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During a physical change, the arrangement of particles may change, but the particles themselves remain the same. For example, ice melting into water changes the arrangement of water molecules.

Front

What happens to the particles in a substance during a chemical change?

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During a chemical change, the bonds between particles break and new bonds form, resulting in the creation of new substances with different properties.

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What is an example of a physical change?

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An example of a physical change is the melting of ice into water.

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What is an example of a chemical change?

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An example of a chemical change is the reaction between vinegar and baking soda that produces carbon dioxide gas.

Front

What is a precipitate?

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A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.