6th Spiral #2 Review

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What is a physical change?

Back

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 dissolving.

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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 the breaking and forming of bonds. Examples include burning, rusting, and cooking.

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What evidence indicates a chemical change has occurred?

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Evidence of a chemical change includes the formation of a new substance, color change, gas production, temperature change, and precipitate formation.

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What is density?

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Density is the mass of an object divided by its volume. It is usually expressed in grams per milliliter (g/mL) or kilograms per cubic meter (kg/m³).

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How do you calculate density?

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Density = Mass / Volume. For example, if an object has a mass of 12.2 grams and a volume of 6 mL, its density would be 2.03 g/mL.

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What happens to the mass of a substance during a physical change?

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The mass of a substance remains the same during a physical change because no new substances are formed.

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What happens to the mass of a substance during a chemical change?

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The mass of a substance is conserved during a chemical change, but it may be transformed into different substances.

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What is an example of a physical change?

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An example of a physical change is dissolving sugar in water. The sugar can be recovered by evaporating the water.

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What is an example of a chemical change?

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An example of a chemical change is the rusting of iron. Iron reacts with oxygen to form iron oxide, a new substance.

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What is the significance of observing color change in a reaction?

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A color change can indicate that a chemical reaction has occurred, suggesting the formation of a new substance.