Physical and Chemical Changes in Matter

Which of the following is an example of a physical change?

• Burning wood

• Melting ice

• Rusting iron

• Baking a cake

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TEKS.SCI.7.6C

DOK Level 2: Skill/Concept

Which of the following is an example of a chemical change?

• Dissolving sugar in water

• Cutting paper

• Cooking an egg

• Boiling water

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TEKS.SCI.7.6C

DOK Level 2: Skill/Concept

How can you differentiate between a physical and a chemical change?

• Physical changes are always reversible, while chemical changes are not.

• Chemical changes involve the formation of new substances, while physical changes do not.

• Physical changes always produce heat, while chemical changes do not.

• Chemical changes are always visible, while physical changes are not.

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TEKS.SCI.7.6C

DOK Level 2: Skill/Concept

Match the following scenarios with the type of change they illustrate.

• Chemical change

• Milk souring

• Physical change

• A piece of paper burning

• Chemical change

• Water evaporating from a puddle

• Chemical change

• A nail rusting over time

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TEKS.SCI.7.6C

DOK Level 2: Skill/Concept

A bicycle chain rusting best illustrates a (a)   change.

• Ice melting in a glass
• Salt dissolving in water
• A bicycle chain rusting
• Water boiling on a stove

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TEKS.SCI.7.6C

DOK Level 2: Skill/Concept

A student observes that a piece of metal has turned reddish-brown after being left outside for several weeks. What type of change has occurred?

• Physical change

• Chemical change

• No change

• Both physical and chemical change

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TEKS.SCI.7.6C

DOK Level 3: Strategic Thinking

Explain why dissolving sugar in water is considered a physical change.

• Because it produces a new substance

• Because it is irreversible

• Because the sugar can be recovered by evaporating the water

• Because it changes the chemical composition of sugar

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TEKS.SCI.7.6C

DOK Level 3: Strategic Thinking

A student mixes vinegar and baking soda, resulting in bubbling and the production of gas. What type of change is this and why?

• Physical change, because it involves mixing

• Chemical change, because a gas is produced

• Physical change, because it is reversible

• Chemical change, because it involves a change in state

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TEKS.SCI.7.6C

DOK Level 3: Strategic Thinking

Describe a real-life scenario where a physical change is beneficial.

• Cooking food to make it edible

• Melting metal to reshape it into tools

• Burning wood for heat

• Rusting of iron to form a protective layer

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TEKS.SCI.7.6C

DOK Level 3: Strategic Thinking

Describe a real-life scenario where a chemical change is beneficial.

• Freezing water to make ice

• Dissolving salt in water for cooking

• Photosynthesis in plants to produce oxygen

• Melting wax to make candles

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TEKS.SCI.7.6C

DOK Level 3: Strategic Thinking