Chemical reactions.

In a chemical equation, is it true that -

• the reactant side and product side can have different numbers of atoms for each element
• there can be different elements on the reactant side and the product side
• an element or compound must be accompanied by a phase change
• the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following models best demonstrates a balanced chemical equation?

• F
• G
• H
• J

Tags

NGSS.MS-PS1-5

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

The reactants are on the left side of the chemical equation.

• True
• False

Tags

NGSS.MS-PS1-5

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-PS1-4

Which of the following BEST describes a chemical reaction?

• A compound is crushed into a fine powder.
• Atoms break apart into even smaller particles.
• Existing electron bonds creak and reattach to other atoms
• Molecules move faster until they fly apart from each other

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

• Physical

• Chemical

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

Tags

NGSS.MS-PS1-5

Which chemical reaction switches 2 elements?

• Double Replacement
• Single Replacement
• Combustion
• Decomposition

The red numbers in the image below represent ________

• subscripts
• coefficients
• I don't know, and don't want to try
• None of the answers are correct

Tags

NGSS.MS-PS1-1