Physical and Chemical Changes in Science

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What is a physical change?

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

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What is a chemical change?

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A chemical change is a change that results in the formation of new chemical substances. Examples include burning, rusting, and digestion.

Front

How does temperature affect chemical reactions?

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Increasing the temperature generally speeds up chemical reactions because it increases the kinetic energy of the particles, causing them to move faster and collide more often.

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What happens to particles during a physical change?

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During a physical change, the arrangement and movement of particles may change, but the particles themselves remain the same.

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What happens to particles 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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What is an example of a physical change?

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An example of a physical change is melting 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 burning wood, which produces ash and gases.

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What are elements?

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Elements are pure substances that cannot be broken down into simpler substances by chemical means. They are made up of only one type of atom.

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What are compounds?

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Compounds are substances formed when two or more elements chemically bond together in fixed proportions. For example, water (H2O) is a compound made of hydrogen and oxygen.

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What are mixtures?

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Mixtures are combinations of two or more substances that are not chemically bonded. They can be separated by physical means.