Evidences of Chemical Reaction

Color change is unexpected mean that it is a

• Chemical change

• Physical change

Tags

NGSS.MS-PS1-2

Is this a physical or chemical change?

• physical change

• chemical change

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

A solid produced by a chemical reaction in solution that separates from the solution is called

• a precipitate.

• a reactant

• a molecule

• the mass of the product

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NGSS.MS-PS1-2

If two substances react and the temperature of the mixture increases, the reaction is ____

• Endothermic

• Not one that produces anything new

• One that needs a catalyst

• Exothermic

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NGSS.MS-PS1-4

Bleaching your hair indicates ......

• A chemical change

• A physical change

Tags

NGSS.MS-PS1-2

Is this a physical or chemical change?

• physical change

• chemical change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

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

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

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

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