Changes in Matter Chemistry

Why is the formation of rust considered a chemical change?

• Rust is more reactive than oxygen

• Rust has the same chemical composition as iron.

• Rust has a lower density than iron.

• Rust has properties that are different from iron and oxygen.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Amanda investigated physical and chemical changes in science class and then classified her changes into two columns shown below.

Column A are the chemical changes and Column B are the physical changes. Which statement below best explains why the processes in Column A are chemical changes?

• The change has formed new substances

• The shape of the substance has changed.

• The change that occurred can be reversed easily.

• The characteristics of the original substance have not changed.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which process is an example of a physical change?

• A peanut butter sandwich is eaten and broken down by enzymes in the stomach.

• Sodium metal and water are combined to form a basic compound and a flammable gas.

• Carrots are cut into small pieces and mixed into a salad.

• Sodium metal and chlorine gas are combined to form sodium chloride, or table salt.

Lena is making a cake to share with her family. She combines the ingredients for the cake, then pours the batter into two pans and bakes the cake for 45 minutes in the oven. What type of change is baking a cake?

• Baking a cake is a physical change, because it can be reversed

• Baking a cake is a chemical change, because you combine chemicals.

• Baking a cake is a chemical change, because it becomes a different substance.

• Baking a cake is a physical change, because the ingredients are the same they are just combined together.

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NGSS.MS-PS1-2

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Ethan is observing chemical and physical properties of a substance. He heats a substance and observes that the substance turns from a brown solid to a black powder. He refers to several chemistry journals that claim this represents a chemical reaction. From his observation and research, he concludes that the substance goes through a chemical change when heated. How can Ethan best defend his conclusion?

• By verifying that the substance is made up of only one type of element.

• By demonstrating that the substance has the same density after it is heated.

• By verifying that the substance is now made up of different molecules than before it was heated.

• By demonstrating that the substance will eventually melt if the temperature continues to increase.

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NGSS.MS-PS1-2

NGSS.MS-PS1-4

Alison finds the total mass of a sample of baking soda, a balloon, and a glass container with vinegar in it. She adds the baking soda to the vinegar and immediately places the balloon over the mouth of the container. After the reaction is complete, she again finds the total mass of the system. Which statement is true about this investigation?

• The mass changes because there was a chemical change that occurred.

• Mass is lost during the reaction because a chemical change is taking place.

• Mass is gained during the reaction because a chemical change is taking place.

• The mass does not change because chemical changes observes the law of conservation of mass.

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NGSS.MS-PS1-5

When paper is burned, the mass of the remaining ash is less than the mass of the original paper. Which statement best explains this result?

• Some of the matter is destroyed during the reaction.

• The volume of the ash is less than the volume of the paper.

• The mass of the ash cannot be accurately determined.

• Some of the matter changed to a gas and was released to the air.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Andrea makes a sugar solution, as shown below. How much sugar did she dissolve in the water?

How much sugar did she dissolve in the water?

• 9 g

• 11 g

• 13 g

• 17 g

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NGSS.MS-PS1-5

Allen mixes fertilizer for his plants at the beginning of the week. He puts 40 g of the fertilizer-water solution in each of seven closed containers and uses one container each day to water his plant. One day, he goes outside to get a container and finds that the solution in it is frozen. How much mass should the frozen solution in the container have?

• 0 g

• 10 g

• 20 g

• 40 g

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

Mrs. Winston decides to do a demonstration for her class with a piece of chalk. Using a balance, Mrs. Winston discovers that the mass of the chalk is 20 g. She then takes the piece of chalk and crushes into a fine powder. The cumulative mass of the fine powder is 20 g. What has Mrs. Winston demonstrated for her class?

• a chemical change involving change of shape and size of matter

• a chemical change involving change of mass

• a physical change involving change of shape and size of matter

• a physical change involving change of mass