Physical and Chemical Changes

Is this an example of a physical or chemical change?

• physical

• chemical

Answer explanation

This is an example of a physical change because it does not involve a change in the chemical composition of the substance. It is still water molecules, just in a different state of matter.

Tags

MS-PS1-2

Is glass breaking a chemical or physical change?

• chemical

• physical

Answer explanation

Glass breaking is a physical change because it does not involve a change in the chemical composition of the glass. The glass is just broken into smaller pieces

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MS-PS1-2

Salt dissolves in water

• physical Change

• chemical change

Answer explanation

Salt dissolves in water is a physical change because it does not involve a chemical reaction. No new substances are made, it is still salt and water.

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MS-PS1-2

Which is a chemical change?

• freezing fruit juice

• slicing a potato

• boiling water

• copper metal turning green

Answer explanation

Copper metal turning green is a chemical change because it involves a chemical reaction that results in a new substance being formed. We know that a new substance is made because an unexpected color change happens.

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MS-PS1-2

Which of the following options provides evidence of a CHEMICAL change?

• Wood is burned releasing ash and smoke

• Rocks separate when soil is sifted

• Boiling water bubbles when heated

• Salt dissolves in water

Answer explanation

Burning wood releases ash and smoke, indicating a chemical change.

Tags

MS-PS1-2

Josh decided to mix some vinegar with baking soda. He knew that a reaction occurred because he made careful observations. He noted that the mixture started to foam up and bubble, and it was white in color. How did Josh know that a chemical reaction occurred?

He was sure a reaction occurred because of

• the color of the mixture

• the smell of the vinegar

• the volume of the mixture

• the formation of a gas

Answer explanation

Josh knew that a chemical reaction occurred because of the formation of a gas. Gas production is a sign of chemical change. (Only if the formation of gas is NOT due to a phase change).

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MS-PS1-2

Physical change is

• A change of matter from one form to another without turning into a new substance.

• A change that occurs when one or more substances produce new substances with different properties.

• The changes that happen to substances during a chemical change.

• The temperature at which a solid becomes a liquid. The melting point of water is 0 °C.

Answer explanation

Physical change is a change of matter from one form to another without turning into a new substance.

Tags

MS-PS1-2

Is the process of water evaporating a physical or chemical change?

• Physical

• Chemical

Answer explanation

The process of water evaporating is a physical change because it involves a change in state from liquid to gas without any chemical reactions.

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MS-PS1-2

What evidence would indicate a chemical change has occurred?

• Unexpected change in color

• Change in shape

• Change in size

• Change in weight or mass

Answer explanation

A change in color is evidence of a chemical change.

Tags

MS-PS1-2

Ms. Guadiamos mixes red paint with blue paint and it becomes purple paint. Student A says that's its a chemical change. Student B says that it's not a chemical change. Who is right and why?

• Student A is right. Change in color is always sign of a chemical change.

• Student A is right. Whenever you mix 2 substances together a chemical change happens.

• Student B is right. The color change did NOT indicate a new substance was created because it was expected to turn purple.

• Student B is right. Color change is NOT a sign of a chemical change.

Answer explanation

The correct answer is Student B. The color change occurred due to the mixing of colors, not the creation of a new substance.

Tags

MS-PS1-2