Signs of a Chemical Reaction

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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, such as melting or freezing.

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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 breaking and forming of bonds between atoms, leading to a change in the chemical composition of the substance.

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What are some signs of a chemical reaction?

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

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How can you differentiate between a physical and chemical change?

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You can differentiate between a physical and chemical change by observing whether the substance's chemical composition changes. If it does, it's a chemical change; if it doesn't, it's a physical change.

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What happens to the molecules during a physical change?

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During a physical change, the arrangement of molecules may change, but the molecules themselves remain the same and retain their chemical properties.

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What happens to the molecules during a chemical change?

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During a chemical change, the bonds between molecules are broken and new bonds are formed, resulting in the creation of new substances with different chemical properties.

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Is melting ice a physical or chemical change?

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Melting ice is a physical change because it changes from solid to liquid without altering its chemical composition (H2O remains H2O).

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Is rusting of iron a physical or chemical change?

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Rusting of iron is a chemical change because it involves the reaction of iron with oxygen to form iron oxide, a new substance.

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What is an example of a chemical change in a solution?

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An example of a chemical change in a solution is when a blue solution and a clear solution are mixed to form a green solution, indicating a new substance has formed.

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What is a precipitate?

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A precipitate is a solid that forms and settles out of a liquid mixture during a chemical reaction.