Unit 2 Test 2

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What is a chemical change?

Back

A chemical change is a process where one or more substances are transformed into different substances with new chemical properties. Examples include burning wood, rusting iron, and baking a cake.

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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 ice, tearing paper, and dissolving salt in water.

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What is rusting?

Back

Rusting is a chemical change that occurs when iron reacts with oxygen and moisture in the environment, forming iron oxide (rust). This process is an example of oxidation.

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What is density?

Back

Density is the mass of a substance divided by its volume. It is a physical property that helps determine whether an object will float or sink in a fluid.

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Why do helium balloons rise in air?

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Helium balloons rise in air because helium is less dense than the surrounding air, creating an upward buoyant force.

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What is a chemical property?

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A chemical property is a characteristic of a substance that can only be observed during a chemical reaction, such as reactivity with acids, flammability, and the ability to rust.

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What is a physical property?

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A physical property is a characteristic of a substance that can be observed or measured without changing its chemical identity, such as color, melting point, and boiling point.

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What is the difference between a chemical change and a physical change?

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A chemical change results in the formation of new substances with different properties, while a physical change does not alter the chemical composition of the substance.

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What are repeating groups of atoms?

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Repeating groups of atoms refer to the arrangement of atoms in a substance that forms a pattern, which can determine the substance's properties.

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What is an example of a chemical change?

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An example of a chemical change is burning wood, where the wood transforms into ash, carbon dioxide, and water.