Chemical Changes

The image shows what happens when cold medicine tablets are placed in room-temperature water. What evidence would indicate that a new substance is produced?

• The tablet dissolves in water

• The water becomes cloudy

• The water level increases slightly

• Bubbles are given off

Tags

NGSS.MS-PS1-2

A student measures out 100 mL of two different clear liquids and then pours one into the other. The mixture, which has a volume of 200 mL, turns bright red, then begins to become quite cold. In this process, the first evidence that a new substance had formed was observed when the –

• student measured the liquids

• volume was seen to be 200 mL

• color changed to bright red

• temperature of the mixture decreased

Tags

NGSS.MS-PS1-2

Four mixtures are made by combining two clear liquids and observations are made. Which results indicate that a new substance has formed?

• Mixture 1: The combined liquids have a greater mass than either of the starting liquids.

• Mixture 2: The liquids, when mixed, produce a white solid which settles to the bottom.

• Mixture 3: The mixture of the two liquids takes the shape of the container they are in.

• Mixture 4: The denser of the two liquids lies below the other less dense liquid.

Tags

NGSS.MS-PS1-2

Which of the following observations is the best indicator that a new substance has been formed?

• A solid has become a liquid.

• A substance has changed color.

• A solid has dissolved in a liquid.

• The volume of a substance increased.

Tags

NGSS.MS-PS1-2

The table records the observations that result from four different combinations. Which combination of substances shows evidence that a new substance was formed?

• Baking soda and vinegar

• Sodium chloride and water

• Oil and water

• Iron filings and sand

Tags

NGSS.MS-PS1-2

Students combine several chemicals and record the observations in their science notebooks. A list of the observed results is given here.

-Production of a gas (bubbles)

-Phase change (solid to liquid)

-A precipitate forms

-Change in shape -

Crystals dissolving

-Heat produced

How many of the observations are evidence that a new substance was formed?

• 3

• 4

• 5

• 6

Tags

NGSS.MS-PS1-2

A granular substance is added to a liquid. Which of the following would provide evidence to suggest a chemical change has taken place?

• The liquid gives off heat.

• The granules dissolve completely

• The volume of the liquid increases.

• The granules seem to get smaller.

Tags

NGSS.MS-PS1-2

Which of the following characteristics is shared by all chemical reactions?

• Produce a precipitate

• Show a color change

• Release heat energy

• Form new substances

Tags

NGSS.MS-PS1-2

All of the following are evidence of a chemical change EXCEPT –

• change in state of matter.

• formation of a gas.

• color change.

• precipitate forms.

Tags

NGSS.MS-PS1-2

What is it called when you mix 2 liquids and a solid forms?

• Condensation

• Precipitate

• Physical Change

• Insulator

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5