Quiz about Chemical Reactions

Question 1

Serena mixed two samples together: a gray solid that smells like flowers and a gray solid that smells like bleach. She analyzed the results and found two ending substances. One of the ending substances was a white solid. This ending substance is made up of the repeating group of atoms shown above. Which of the diagrams to the left shows the repeating groups of atoms that make up the samples Serena mixed together?

Accepted Answer

Diagram D

Answer

Diagram A

Answer

Diagram B

Answer

Diagram C

Question 2

Tiana is a chemist who is making a chemical to add to swimming pools in order to make the water safer. She mixed two solid substances together in a sealed container. The diagram above shows the repeating groups of atoms that make up the two starting substances.

After mixing, Tiana found two liquid substances in the sealed container. (Nothing had escaped.) Which of the diagrams to the left shows the repeating groups of atoms that make up the ending substances?

Accepted Answer

Diagram C

Answer

Diagram A

Answer

Diagram B

Answer

Diagram D

Question 3

Damian mixed two samples together: a red liquid that smells irritating and a black solid with no smell. He analyzed the results and found two ending substances. One of the ending substances was a yellow solid. This ending substance is made up of the repeating group of atoms shown above. Which of the diagrams to the left shows the repeating groups of atoms that make up the samples Damian mixed together?

Accepted Answer

Diagram B

Answer

Diagram A

Answer

Diagram C

Answer

Diagram D

Question 4

Santiago is a chemist working to make a new kind of antacid, which is a medicine that helps with stomach pain. He mixed two powdery solid substances together in a sealed container. The diagram above shows the repeating groups of atoms that make up the two starting substances.

After mixing, Santiago found two liquid substances in the sealed container. (Nothing had escaped.) Which of the diagrams to the left shows the repeating groups of atoms that make up the ending substances?

Accepted Answer

Diagram D

Answer

Diagram A

Answer

Diagram B

Answer

Diagram C

Question 5

What is the result of a chemical reaction?

Accepted Answer

New substances with different properties from the starting materials are formed.

Answer

The starting materials disappear without a trace.

Answer

The physical state of the starting materials changes.

Answer

The starting materials are recovered unchanged.

Question 6

What is a reactant in a chemical reaction?

Accepted Answer

A substance that is consumed in the reaction.

Answer

A substance that is produced in the reaction.

Answer

A substance that speeds up the reaction.

Answer

A substance that remains unchanged in the reaction.

Question 7

What is an endothermic reaction?

Accepted Answer

A reaction that absorbs heat.

Answer

A reaction that releases heat.

Answer

A reaction that produces light.

Answer

A reaction that produces sound.

Question 8

What is a chemical reaction?

Accepted Answer

A process where substances change into new substances with different properties.

Answer

A process where substances are mixed but retain their original properties.

Answer

A process where substances are dissolved in water.

Answer

A process where substances are heated but do not change.

Question 9

What is the result of a chemical reaction between vinegar and baking soda?

Accepted Answer

Carbon dioxide gas

Answer

Water

Answer

Oxygen gas

Answer

Hydrogen gas

Question 10

What happens to the atoms in a chemical reaction?

Accepted Answer

They are rearranged to form new substances.

Answer

They are destroyed.

Answer

They are created.

Answer

They disappear.

Question 11

Which of the following is a sign of a chemical reaction?

Accepted Answer

Change in color

Answer

Change in shape

Answer

Change in size

Answer

Change in texture

Question 12

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

Accepted Answer

Burning wood

Answer

Melting ice

Answer

Dissolving sugar in water

Answer

Breaking a glass

Question 13

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

Accepted Answer

Chemical changes create new substances, physical changes do not

Answer

Chemical changes are reversible, physical changes are not

Answer

Physical changes create new substances, chemical changes do not

Answer

Physical changes involve energy, chemical changes do not

Question 14

Marisol mixed two samples together: a brown liquid with no smell and a colorless gas that smells irritating. She analyzed the results and found two ending substances. One of the ending substances smelled sweet. This ending substance is made up of the repeating group of atoms shown above. Which of the diagrams to the left shows the repeating groups of atoms that make up the samples Marisol mixed together?

Accepted Answer

Diagram A

Answer

Diagram B

Answer

Diagram C

Answer

Diagram D

Question 15

Jamie works at a company that makes cleaning chemicals. She is trying to make a chemical that smells like flowers. She took two samples that were gases at room temperature and mixed them in a sealed container. The diagram above shows the repeating groups of atoms that make up the two starting substances.

After mixing, Jamie found two substances that smelled like flowers in the sealed container. (Nothing had escaped.) Which of the diagrams to the left shows the repeating groups of atoms that make up the ending substances?

Accepted Answer

Diagram D

Answer

Diagram A

Answer

Diagram B

Answer

Diagram C

Question 16

Patrik works at a company that makes paper and needs a chemical to make the paper brighter. He mixed two colorless substances together in a sealed container. The diagram above shows the repeating groups of atoms that make up the two starting substances.

After mixing, Patrik found two white substances in the sealed container. (Nothing had escaped.) Which of the diagrams to the left shows the repeating groups of atoms that make up the ending substances?

Accepted Answer

Diagram B

Answer

Diagram A

Answer

Diagram C

Answer

Diagram D

Question 17

A chemist mixed two substances together: a blue powder with no smell and a colorless liquid with a strong smell. Their repeating groups of atoms are shown above on the left. After they were mixed, the chemist analyzed the results and found two substances. One ending substance had the repeating group of atoms shown above on the right.

Is the ending substance the same substance as the blue powder? What happened to the atoms of the starting substances when the ending substances formed? Be sure to explain your answers to both of these questions.

Accepted Answer

The ending substance is a different substance than the blue powder.

Answer

I really don't know and I am too lazy to figure it out.

Answer

The ending substance is not a different substance from the blue powder.

Answer

The ending substance is the same substance as the blue powder.

Question 18

Sahil watched a demonstration in which a scientist combined two substances in a sealed container and analyzed the results. The ending substances did not look the same as the starting substances. Sahil was given a diagram with the repeating groups of atoms that make up the starting substances, plus information about the properties of the starting and ending substances. He created a model of the repeating groups of atoms that might make up the two ending substances. Does his model correctly show why the properties of the ending substances are different from the properties of the starting substances?

Accepted Answer

No, the model is incomplete.

Accepted Answer

No, because one atom is missing from the starting samples.

Answer

Yes, the model is completely correct.

Answer

Yes, all the atoms are still there.

Question 19

The diagram above shows the repeating groups of atoms that make up two samples. Will the properties of the two samples likely be the same or different? (Examples of properties are smell, color, and the temperature at which a substance melts.)

Accepted Answer

The properties will likely be different because the repeating groups of atoms that make up each sample are different.

Answer

The properties will likely be different because there are more repeating groups of atoms in Sample 2.

Answer

The properties will likely be the same because the repeating groups of atoms that make up the two samples have the same number of atoms.

Answer

The properties will likely be the same because the repeating groups of atoms that make up the two samples have two of the same types of atoms.

Question 20

What is the law of conservation of mass in chemical reactions?

Accepted Answer

Mass is neither created nor destroyed in a chemical reaction.

Answer

Mass is lost during a chemical reaction.

Answer

Mass is gained during a chemical reaction.

Answer

Mass is converted into energy during a chemical reaction.

Question 21

Which of the following is an example of an exothermic reaction?

Accepted Answer

Combustion of gasoline

Answer

Photosynthesis in plants

Answer

Melting of ice

Answer

Evaporation of water

Question 22

What is the role of a catalyst in a chemical reaction?

Accepted Answer

It speeds up the reaction without being consumed.

Answer

It increases the temperature of the reaction.

Answer

It decreases the temperature of the reaction.

Answer

It is consumed in the reaction to produce energy.

Question 23

In a chemical equation, what does the arrow (->) represent?

Accepted Answer

The direction of the reaction

Answer

The equality of reactants and products

Answer

The speed of the reaction

Answer

The temperature at which the reaction occurs

Question 24

Which of the following observations indicates a chemical reaction has occurred?

Accepted Answer

A gas is produced and bubbles form

Answer

A solid melts into a liquid

Answer

A liquid evaporates into a gas

Answer

A substance is cut into smaller pieces

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