Chemical and Physical 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 freezing) and changes in 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 rusting of iron and souring of milk.

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What happens to water when it is heated to form steam?

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When water is heated to form steam, it undergoes a physical change as it changes from a liquid to a gas without changing its chemical composition.

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What is an example of a chemical change?

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Baking a cake is an example of a chemical change because it involves a chemical reaction that produces new substances.

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What occurs when iron rusts?

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When iron rusts, it undergoes a chemical change as it reacts with oxygen and moisture in the air to form iron oxide, a new substance.

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

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A physical change does not alter the chemical composition of a substance, while a chemical change results in the formation of new substances.

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What happens to milk when it sours?

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When milk sours, it undergoes a chemical change due to the action of bacteria that produce lactic acid, resulting in a new substance.

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What is an example of a physical change?

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Inflating a tire with air is an example of a physical change because it changes the shape and volume of the tire without altering its chemical composition.

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What is the role of heat in physical changes?

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Heat can cause physical changes by providing energy that allows substances to change state, such as melting ice into water.

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Can a physical change be reversed?

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Many physical changes can be reversed, such as freezing and melting, but some may not be easily reversible.