Signs of a Chemical Reaction

Students performed multiple investigations at different stations in the classroom.  The data collected is listed in the table. The observations from which investigations provide evidence that a new substance was formed?

• Stations 1, 3, 4, and 5

• Stations 2, 5, and 6

• Stations 1, 3, and 4

• Stations 1, 2, 3, and 4

Tags

NGSS.MS-PS1-2

A clear liquid from a flask is poured into another clear liquid in a beaker. Which of the following results of this procedure would indicate a new substance was formed?

• The level of the substance in the beaker is higher after the other liquid is added.

• A yellow solid forms and then settles to the bottom of the beaker.

• Small white crystals are left behind in the flask that held the first liquid.

• The mass of the combined liquids is greater than either original liquid.

Tags

NGSS.MS-PS1-2

Four students performed four different investigations by combining different substances. Which of the observations is most indicative of a chemical reaction?

• investigation 1

• investigation 2

• investigation 3

• investigation 4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student places a piece of a potato into a container of hydrogen peroxide. One observation the student makes is that bubbles form around the potato. The presence of bubbles might indicate the formation of a new substance because bubbles - 

• could show that a gas is forming.

• always rise to the top of a liquid. 

• are almost always perfectly spherical.

• usually burst after a few minutes.

Tags

NGSS.MS-PS1-2

When a new substance forms as a result of a chemical reaction, what type of change has occurred?

• Chemical Change

• Physical Change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which is NOT an indication of a chemical change?

• Temperature Change

• Shape Change

• Formation of a precipitate

• Production of light

Tags

NGSS.MS-PS1-2

Which statement is not a description of a chemical reaction?

• A solid is dropped into a beaker of liquid and a gas is released.

• A solid is dropped into a beaker of liquid and an explosion occurs.

• Two liquids are mixed in a beaker and a solid forms at the bottom of the beaker.

• A liquid is heated in the sun and half of it evaporates.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Two liquids are mixed together.  Which of the following does NOT identify the formation of a new substance?

• A gas is produced.

• One liquid dissolves into the other.

• The temperature changes.

• A solid is formed.

Tags

NGSS.MS-PS1-2

An increase or decrease in _________________and the production of light are both signs that a chemical reaction may have occurred.

• atoms

• temperature

• odor

• molecule

Tags

NGSS.MS-PS1-2

What is PROOF that a chemical change has occured?

• a new substance with different properties is created.

• you can put the reactants back together

• the substance changes state, solid to liquid or liquid to solid.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5