Physical and Chemical Changes

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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 changes in state (like melting or boiling), shape, or size.

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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. It involves a chemical reaction and the rearrangement of atoms. Examples include burning, rusting, and digestion.

Front

What happens to a candle when it burns?

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When a candle burns, it undergoes a chemical change as the wax reacts with oxygen in the air to produce heat, light, carbon dioxide, and water.

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Is bending metal a physical or chemical change?

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Bending metal is a physical change because it alters the shape of the metal without changing its chemical composition.

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What is an example of a new substance forming?

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Lighting a match is an example of a new substance forming, as it produces heat, light, and combustion products that are different from the original matchstick.

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What occurs when fireworks explode?

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When fireworks explode, a chemical change occurs as the chemicals in the fireworks react to produce light, sound, and gas.

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Is boiling water a physical or chemical change?

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Boiling water is a physical change because it changes from liquid to gas (steam) without altering its chemical composition.

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What is the difference between a physical change and a chemical change?

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A physical change involves changes in physical properties without altering the substance's chemical identity, while a chemical change results in the formation of new substances.

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Can a physical change be reversed?

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Many physical changes can be reversed (e.g., freezing and melting water), but chemical changes usually cannot be reversed easily.

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What is an example of a physical change in everyday life?

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Examples of physical changes include chopping vegetables, dissolving sugar in water, and freezing juice.