Unit 2 Chemistry Review

The student carrying out this experiment inferred that a chemical reaction occurred. What evidence supports this inference?

• A darker-colored 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 pictures above shows a blue liquid being added to a clear liquid. Which of the following provides the best evidence that a chemical reaction may have occurred?

• The solution turned light blue.

• The temperature remained the same.

• A precipitate has formed.

• The volume increased.

Tags

NGSS.MS-PS1-2

Drew measured out some yeast and some of sugar, then mixed them in some water. He quickly stretched a balloon over the flask and taped it down. He swirled the flask to mix the yeast, sugar, and water.

After several minutes, he noticed small bubbles rising along the side of the flask as the balloon began to slowly inflate. Drew quickly inferred that ….

• a physical change was occurring.

• the bubbles indicate a new gas was formed and a chemical change had occurred.

• the water, sugar, and yeast were products of a chemical reaction.

• the gas was harmful.

Tags

NGSS.MS-PS1-2

In which investigation is it least likely that the liquids chemically reacted?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A scientist spills some hydrochloric acid (HCl) on a table, so she adds some baking soda (NaHCO₃) for safety purposes. Which observation would indicate a chemical reaction occurred?

• The hydrochloric acid and baking soda combine to form gas bubbles

• The baking soda absorbed the hydrochloric acid

• Some of the baking soda dissolved in the hydrochloric acid

• The hydrochloric acid evaporated, leaving only baking soda

Tags

NGSS.MS-PS1-2

How many atoms are represented in the reactants?

• 13

• 28

• 3

• 23

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

How many carbon atoms are there in a single molecule of CH₃CH₂Br?

• 1

• 5

• 3

• 2

Tags

NGSS.MS-PS1-1

Which substance has the most oxygen atoms?

• I

• II

• III

• IV

Tags

NGSS.MS-PS1-1

In which of the following compounds are there twice has many oxygen atoms as there are carbon atoms?

• 2C₂O

• 2CO

• 3HCO₂

• Al₂(CO₃)₃

Tags

NGSS.MS-PS1-1

How many total elements are there in a molecule of CH₃CH₂OH?

• 6

• 3

• 9

• 18

Tags

NGSS.MS-PS1-1