Physical and Chemical Change Lesson

Chemical changes result in new substances, but physical changes do not. Which process is an example of a physical change?

• Sodium and water are combined and form sparks.
• Bleaching lightening hair color
• A loaf of bread being sliced into pieces.
• Sodium and chlorine are combined to form table salt.

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NGSS.MS-PS1-4

It is important to understand the differences between chemical and physical changes. Chemical changes result in new substances, but physical changes do not. Which process is an example of a physical change?

• Water turns to steam when boiled over a Bunsen burner.
• Carbon combines with oxygen to form carbon dioxide gas.
• Water breaks down into hydrogen and oxygen gases over time.
• Limestone breaks down into lime and carbon dioxide when heated.

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NGSS.MS-PS1-4

There are several differences between chemical and physical changes. Which statement is true of a chemical change, but not true of a physical change?

• A chemical change can produce warmth.
• A chemical change can be easily changed back.
• A chemical change can separate a mixture into its components.
• A chemical change can combine substances without altering them.

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NGSS.MS-PS1-5

A chemical change of matter takes place when one or more substances change into entirely new substances with different properties. Although physical changes affect the appearance of a substance, chemical changes affect its composition. Which process indicates that a chemical change is taking place?

• A lake freezes over into ice.
• A metal bar is rolled into a flat sheet.
• Vinegar bubbles when baking soda is added.
• Sand, water, and salt combine to form a mixture.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Rita wants to make some toast for breakfast. She puts a slice of bread in the toaster. After 10 minutes, Rita notices that the sides of the bread are black. What caused this chemical change to take place?

• added warmth
• added mass
• added volume
• added particles

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NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

Shanti mixes 39 g of potassium with 39 g of chlorine. She obtains 74 g of potassium chloride and recovers 4 g of unreacted chlorine. Do Shanti’s results confirm the law of conservation of mass?

• No, because no potassium is left over.
• Yes, because the mass of all the reactants is accounted for.
• Yes, because all of the potassium reacted with the chlorine.
• No, because the mass of the potassium chloride is greater than the amount of potassium used.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

What should a scientist do if they want to speed up the chemical reaction?

• Increase the density of the substance
• Decrease the density of the substance
• Increase the temperature of the substance
• Decrease the temperature of the substances

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NGSS.HS-PS1-5