Chemical vs 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 changes the molecular structure of the substance. Examples include burning, rusting, and cooking.

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Is a change in color always a chemical change?

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No, a change in color is not always a chemical change. It can also be a physical change, such as when a substance is mixed with another that changes its appearance without altering its chemical structure.

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What is an example of a heterogeneous mixture?

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An example of a heterogeneous mixture is salad dressing, where oil and vinegar separate into different layers.

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What is an example of a homogeneous mixture?

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An example of a homogeneous mixture is saltwater, where the salt is completely dissolved in the water and cannot be distinguished from it.

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What happens during the freezing of juice?

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During the freezing of juice, the liquid changes to a solid state without changing its chemical composition, making it a physical change.

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What is an example of a physical change in nature?

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An example of a physical change in nature 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 burning wood, which produces ash, smoke, and gases.

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How can you tell if a change is chemical?

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You can tell if a change is chemical if it produces gas, changes color, releases heat or light, or forms a precipitate.

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What is rusting?

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Rusting is a chemical change that occurs when iron reacts with oxygen and moisture in the air, forming iron oxide (rust).