Chemical Reactions Review

Priya is conducting a science experiment. Which of the following observations indicates a chemical reaction?

• Priya grinds large brown rocks into smaller pieces to produce a brown powder.

• Priya adds water to a dark blue liquid to produce a light blue liquid.

• Priya mixes a colorless liquid and a gray solid to produce a gas and a green liquid.

• Priya boils liquid water to produce steam.

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NGSS.MS-PS1-2

Nora and Elijah are conducting an experiment in their chemistry class. They pour two different liquids into a glass beaker. Which of the following would indicate that a chemical reaction occurred between the two liquids?

• the complete mixing of the two liquids.

• a decrease in total volume of the liquids.

• the formation of a solid in the beaker.

• an increase in total mass of the liquids.

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NGSS.MS-PS1-2

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

• boiling water turning into steam

• dissolving table salt in a glass of water

• burning a marshmallow

• cutting a piece of wood into small wood chips

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Ethan is conducting an experiment in a closed system. He starts with 10 grams of hydrogen and 80 grams of oxygen. After the reaction, he finds 90 grams of water. Which of the following demonstrates conservation of atoms?

• Option A

• Option B

• Option C

• Option D

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NGSS.MS-PS1-5

During a science experiment, Aria and Samuel mixed two chemicals in a sealed container. Which of the following statements is correct about the mass inside the container after the reaction?

• The total mass of the products is more than the total mass of the reactants.

• The total mass of the products is less than the total mass of the reactants.

• The total mass of the products is equal to the total mass of the reactants.

• The total mass of the products is unrelated to the total mass of the reactants.

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NGSS.MS-PS1-5

A closed system is one in which:

• reactants and products can both enter or leave.

• reactants cannot enter or leave, but products can.

• reactants can enter or leave, but products cannot.

• reactants and products cannot enter or leave.

Hannah and William are conducting an experiment in their chemistry class. They have two liquids: Liquid A, which is clear and colorless, and Liquid B, which is clear and light blue. When they combine the two liquids in a closed system, they observe a cloudy, pale green solution forming. Which of the following describes what has occurred?

• a chemical reaction where mass was conserved

• a physical reaction where mass was conserved

• a physical reaction where mass was not conserved

• a chemical reaction where mass was not conserved

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is an example of using a chemical process to release energy?

• dissolving copper chloride powder in a beaker of water

• cutting wood into small wood chips

• using a battery to power a flashlight

• heating an ice cube to melt it

When an endothermic chemical reaction absorbs thermal energy from the environment,

• the temperature of the products is higher than the temperature of the reactants.

• the temperature of the products is lower than the temperature of the reactants.

• there is no change in temperature, but there is a change in state.

• the temperature of the products is the same as the temperature of the reactants.

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NGSS.MS-PS1-4

NGSS.MS-PS3-4

Your friend Mary tells you she has a great idea for making a new product to keep the wires from her headphones from tangling. She makes a version of her product from materials she finds at home. This first version of her product is known as

• a constraint.

• a prototype.

• a criterion.

• an experiment.

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NGSS.MS-ETS1-4