Chemical & 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), 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 digestion.

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What happens when glass is broken?

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Breaking glass is a physical change because it alters the shape and size of the glass without changing its chemical composition.

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What happens when wood is burned?

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Burning wood is a chemical change because it transforms the wood into ash, smoke, and gases, creating new substances.

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What kind of change is toasting bread?

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Toasting bread is a chemical change because it involves a reaction that changes the bread's chemical structure, resulting in a different flavor and texture.

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What happens when paper is ripped?

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Ripping paper is a physical change because it changes the size and shape of the paper but does not alter its chemical composition.

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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), which is a different substance.

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What are examples of physical changes?

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Examples of physical changes include melting ice, boiling water, dissolving sugar in water, and breaking a pencil.

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What are examples of chemical changes?

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Examples of chemical changes include baking a cake, burning gasoline, and reacting vinegar with baking soda.

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How can you tell if a chemical change has occurred?

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