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 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 the breaking and forming of bonds between atoms, leading to a change in the chemical composition of the substance. Examples include rusting, combustion, and digestion.

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What are some indicators of a chemical change?

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

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What are some examples of physical changes?

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

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How can you differentiate between physical and chemical changes?

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You can differentiate between physical and chemical changes by observing whether the substance's chemical composition changes (chemical change) or if it retains its original composition (physical change).

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What is the law of conservation of mass in relation to chemical changes?

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The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants equals the total mass of the products.

Front

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 properties.

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Can a physical change be reversed?

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Many physical changes are reversible, such as freezing and melting, but some may not be easily reversible, like breaking a glass.

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Can a chemical change be reversed?

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Chemical changes are often not easily reversible. For example, burning wood creates ash and gases that cannot be converted back into wood.