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 changes in shape, size, or state of matter.

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 the rearrangement of atoms. Indicators include color change, gas production, and temperature change.

Front

What are some indicators of a chemical change?

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Indicators of a chemical change include the formation of gas (bubbles), color change, temperature change, and the formation of a precipitate.

Front

How can you differentiate between physical and chemical changes?

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Physical changes do not create new substances and can often be reversed, while chemical changes produce new substances and are usually irreversible.

Front

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

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During a physical change, the arrangement or state of the particles may change, but the particles themselves remain the same.

Front

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

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During a chemical change, the bonds between atoms are broken and new bonds are formed, resulting in the creation of new substances.

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Can a physical change be reversed? Give an example.

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Yes, many physical changes can be reversed. For example, melting ice can be reversed by refreezing the water.

Front

Can a chemical change be reversed? Give an example.

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Chemical changes are often not reversible. For example, burning wood creates ash and gases, which cannot be turned back into wood.

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What is an example of a physical change involving temperature?

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An example of a physical change involving temperature is the melting of ice into water when heat is applied.

Front

What is an example of a chemical change involving gas formation?

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An example of a chemical change involving gas formation is the reaction between baking soda and vinegar, which produces carbon dioxide gas.