Chemical Reaction

Evidence of a chemical reaction includes anything that shows -

• a new substance has been formed

• a solid has dissolved in a liquid.

• an interaction between two gases.

• a change in the state of matter.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

A chemical reaction is represented in the equation provided.

3H2+3Cl2 (ARROW) ?HCl

What number needs to go in front of the HCl to balance the equation?

• 2

• 3

• 5

• 6

Tags

NGSS.MS-PS1-5

A scientist spilled a few drops of dilute hydrochloric acid (HCl) on a lab table. For safety

purposes, the scientist sprinkled some baking soda (NaHCO3) onto the spill. Which

observation would provide the best evidence that a chemical reaction occurred?

• The baking soda and hydrochloric acid combined, and bubbles formed.

• The baking soda absorbed the hydrochloric acid.

• Some of the baking soda dissolved in the hydrochloric acid.

• The hydrochloric acid evaporated, leaving only the baking soda.

Tags

NGSS.MS-PS1-2

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-PS1-4

NGSS.MS-PS1-5

Which substance most likely caused a new substance to be formed when mixed with water?

• Substance 1

• Substance 2

• Substance 3

• Substance 4

Tags

NGSS.MS-PS1-2

Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?

• The shape of the coal changes.

• Oxygen is present.

• A new substance is produced.

• Coal is made up of more than one element.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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 CuSO solution turned blue when the zinc metal was added.

• None of these

Tags

NGSS.MS-PS1-2

Which statement is not supported by the student’s observations?

• A chemical reaction takes place between magnesium and hydrochloric acid.

• A gas is released in Test Tube 2.

• The substances in both test tubes are reactive only at high temperatures.

• Energy is released in the reaction involving hydrochloric acid.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Which statement provides evidence that a chemical reaction occurs?

• A gas is present.

• The total number of atoms remains unchanged.

• The state of matter remains the same.

• A brown gas is produced.

Tags

NGSS.MS-PS1-2