Evidence of Chemical Reaction

In a chemical reaction, everything to the right of the arrow is called ______________.

• Products

• Yields

• Molecules

• Reactants

In a ___________change, a substance changes into a different substance.

• Physical

• Chemical

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Toasting Bread

• Physical Change

• Chemical Change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

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

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

Which of the following is an example that includes evidence of a chemical reaction?

• A sample of zinc is placed in water and it settles to the bottom

• A solid block of ice is heated and it completely melts into a liquid. 

• Sugar that is burned gives off an odor and turns brown and then black.

• A tomato is placed into a blender and chopped up into smaller pieces.

Tags

NGSS.MS-PS1-2

In a container, a solid consisting of clear crystals is combined with a blue liquid and the following observations are obtained.
 How many of the listed observations indicate a new substance was formed?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-2

For an investigation a student poured a blue solution of CuSO₄ into a beaker. The student placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes.
The student inferred that a chemical reaction occurred. What evidence supports this inference?

• A dark solid formed on the zinc metal.

• 
  The zinc metal remained silver-colored and shiny

• The CuSO₄ solution turned blue when the zinc metal was added.

• None of these

Tags

NGSS.MS-PS1-2

Two clear colorless solutions were combined.
The student observed that the temperature changed from 25 •C to 23 •C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?

• One of the original compounds came out of solution

• The solutions reacted chemically

• Some of the water froze into ice crystals

• Rapid evaporation of water occurred, leaving a solid

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5