Counting Atoms and Chemical Reactions

True or False
In a chemical reaction, no new atoms are created, and no atoms are destroyed. 

• true

• false

Tags

NGSS.MS-PS1-5

Which of the following 2 are chemical reactions?

• sugar dissolving in water

• water turning into steam

• burning wood

• mixing baking soda and vinegar

• tearing paper

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

In a chemical reaction, if the reactants are heated, the reaction usually happens

• slower

• faster

• at the same rate

• in a smaller volume

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NGSS.MS-PS1-2

NGSS.MS-PS1-4

Which of these is NOT a sign that a chemical change has occurred?

• A loss of transparency

• An unexpected color change

• A temperature change

• The formation of a precipitate

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NGSS.MS-PS1-2

In a chemical reaction, bonds are broken and new bonds are formed that create new substances. The bonds that are broken are called what?

• Reactants

• Products

• Atoms

• Catalysts

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NGSS.MS-PS1-1

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same

• that matter can only be changed into new substances by introducing a catalyst

• that matter exists in the same state throughout any chemical change

• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

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NGSS.MS-PS1-5

How many Al atoms are in this compound?         4Al₂O₃

• 2

• 8

• 6

• 4

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NGSS.MS-PS1-1

How many F atoms are in this compound?
6MgF₂ 

• 2

• 6

• 8

• 12

Tags

NGSS.MS-PS1-1

___________________ are the elements are compounds that leave (are formed in) a chemical
reaction.

• Polymers

• Bonds

• Reactants

• Products

Tags

NGSS.MS-PS1-2

A chemical change is different than a physical change because in a chemical change

• Chemicals are used

• Molecules do not physically touch

• A new substance is formed and in a physical change no new substance is formed

• The change can be seen but in a physical change it cannot

Tags

NGSS.MS-PS1-2