Changes in Matter/Law of Conservation

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

• A chemical change results in the formation of new substances, while a physical change does not.

• A physical change results in the formation of new substances, while a chemical change does not.

• Both chemical and physical changes result in the formation of new substances.

• Neither chemical nor physical changes result in the formation of new substances.

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NGSS.MS-PS1-2

List two examples of physical changes.

• Melting of ice and tearing of paper

• Burning of wood and rusting of iron

• Cooking an egg and baking a cake

• Digesting food and rotting fruit

Which of the following are examples of chemical changes?

• Melting ice

• Melting of ice

• Burning of wood

• Boiling of water

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What happens during a physical change?

• New substances formed.

• The identity of a substance is changed.

• A chemical reaction occurs.

• A property of a substance changes, but its identity stays the same.

Which of the following is a chemical change?

• water freezing

• paper being torn

• cake baking

• ice melting

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NGSS.MS-PS1-2

Which of the following would cause a chemical change in a piece of wood?

• hammering a nail into the wood

• burning the wood

• painting the wood

• sawing the piece of wood in half

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NGSS.MS-PS1-2

Scenario: John is conducting an experiment where he adds a piece of zinc to sulfuric acid. He observes bubbles forming and notices that the beaker feels warm to the touch.

Question: What type of change is John most likely observing, and what evidence supports this conclusion?

• Physical change; the formation of bubbles and the warm beaker

• Chemical change; the bubbles form and the beaker becoming warm

• Physical change; the zinc dissolving and the temperature rising

• Chemical change; the zinc dissolving and no temperature change

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A physical change is taking place when

• a nail rusts.

• onions are chopped.

• a piece of apple rots.

• a piece of paper burns.

Which is a clue that a chemical change has occurred?

• A beaker becomes warm when you mix two room-temperature liquids in it.

• A liquid forms bubbles when it reaches a high temperature.

• Water changes color when food coloring is added.

• A car door feels hot when touched in summer.

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NGSS.MS-PS1-2

Scenario: A class observes what happens when vinegar is added to baking soda. They record the following data:

Which of the following observations supports the conclusion that a chemical change occurred?

• The formation of bubbles and the temperature change both indicate a chemical change.

• Only the bubbles indicate a chemical change; the temperature change is a physical change.

• The cloudiness indicates a chemical change, while the bubbles and temperature change are physical changes.

• None of these observations indicate a chemical change because the color did not change.

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NGSS.MS-PS1-2

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