JDES 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 melting, freezing, and folding.

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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 the rearrangement of atoms and can be identified by changes in color, temperature, or the production of gas.

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What happens to ice when it melts?

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When ice melts, it undergoes a physical change from solid to liquid due to the increase in temperature, but its chemical composition (H2O) remains the same.

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What are some indicators of a chemical reaction?

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Indicators of a chemical reaction include a change in color, temperature, the formation of a precipitate, and the production of gas.

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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 environment, resulting in the formation of iron oxide (rust).

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What is evaporation?

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Evaporation is the process by which liquid water turns into water vapor (gas) when heated, which is a physical change.

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How can you identify a physical change?

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A physical change can be identified if the substance's chemical identity remains the same, and it can often be reversed, such as freezing and melting.

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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 with different properties.

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What happens to water when it is heated?

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When water is heated, it can undergo a physical change by boiling and evaporating into gas, depending on the temperature.

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

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An example of a physical change is folding a piece of paper, which changes its shape but not its chemical composition.