Evidence of a Chemical Change

Which of the following examples shows that a chemical reaction has occurred? 

• A rock breaks into smaller pieces when it is struck with a hammer.

• Rust forms on a hammer that has been left outside to long. 

• A cup of water turns pink when a few drops of red food coloring are added. 

• A solid is formed when heat is removed from a sample of water. 

Tags

NGSS.MS-PS1-2

Four students performed four different investigations by combining different substances. Their results are shown in the table provided. In which experiment are new substances being formed?

• Experiment 1

• Experiment 2

• Experiment 3

• Experiment 4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Hydrogen peroxide breaks down to form water and oxygen gas. Which observation is evidence that a chemical reaction has occurred?

• The mass of the solution remains the same.

•  Phase changes are observed.

•  The color of the solution remains clear.

• The temperature of the solution increases. 

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.

Tags

NGSS.MS-PS1-2

The only sure evidence of a chemical reaction is.... (a)  

• the formation of a gas.

• a color change.

• the production of a new substance.

Tags

NGSS.MS-PS1-2

During an experiment, a student observes a color change when two substances are mixed. What type of evidence does this provide?

• Evidence of a physical change

• Evidence of a chemical change

• Evidence of a state change

• Evidence of a mixture

Tags

DOK Level 3: Strategic Thinking

TEKS.SCI.6.6E

Which observation(s) might be used as evidence that a chemical reaction occurred?

• Color change

• Odor change

• change in temperature

• All of the above

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is evidence of a chemical change?

• Change in shape

• Change in size

• Production of a gas

• Melting

Tags

DOK Level 1: Recall

TEKS.SCI.6.6E

Which observation(s) might be used as evidence that a chemical reaction occurred?

• Color change

• Odor change

• Properties change

• All of the above

Tags

NGSS.MS-PS1-2

During an experiment, a student observes a color change when two substances are mixed. This provides (a)  

• Evidence of a physical change

• Evidence of a chemical change

• Evidence of a state change

• Evidence of a mixture

Tags

DOK Level 3: Strategic Thinking

TEKS.SCI.6.6E