Chem 3A

Which is the best evidence that a chemical change in matter has occurred?

• A solid melts.

• A gas is produced.

• Matter is destroyed during a chemical reaction.

Tags

NGSS.MS-PS1-2

A marshmallow is made mostly of sugar and air. When heated in a microwave oven, a marshmallow increases in size to nearly twice its normal volume but does not produce any new substances. Which best describes the change in the marshmallow?

• The heated air expands as a physical change occurs.

• The heated air expands as a chemical change occurs

• The heated air contracts as a physical change occurs.

• The heated air contracts as a chemical change occurs.

Tags

NGSS.MS-PS3-4

This general chemical equation shows an example of energy availability in a theoretical reaction.

Which statement is true about the equation?

• The equation is missing products

• The equation is missing reactants.

• Energy was released.

• Energy was absorbed.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-5

A student performs an experiment and the results are shown below.

Before: Iron filings are brown, small, and magnetic; copper sulfate crystals are blue, brittle, and not magnetic.

​After: The copper formed was reddish, solid, and not magnetic; iron sulfide solution was colorless and not magnetic.

Which statement supports that a chemical reaction took place?

• Changes in color occurred.

• A new substance was formed.

• A physical change in the iron occurred.

• The original substances were present after.

Tags

NGSS.MS-PS1-2

Which chemical change occurs due to mixing baking soda and vinegar?

• combustion

• gas production

• heat production

Tags

NGSS.MS-PS1-2

Which best describes a solid produced in a solution during a chemical reaction?

• acid

• solute

• reactant

• precipitate

The drawing shows solid carbon dioxide changing into carbon dioxide gas.

Which statement describes the relationship between the solid carbon dioxide and the carbon dioxide gas after all of the solid has changed to gas?

• They have the same volume.

• The gas has less volume than the solid.

• They have the same mass.

• The gas has less mass than the solid.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

A piece of paper burns, producing heat and light. Which best describes the process of burning?

• Burning is a physical change. The paper mixes with the oxygen in the air, producing heat and light.

• Burning is a chemical change. The paper reacts with the oxygen in the air, producing heat and light.

• Burning is a physical change. The paper changes from a solid to a gas, producing heat and light.

• Burning is a chemical change. The paper breaks down in sunlight, producing heat and light.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which best describes a substance that changes from a liquid to a solid?

• The substance gains mass.

• The substance loses volume

• a physical change has occurred

• a chemical change has occurred

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which indicates a chemical reaction is occurring?

• a substance melting

• a substance evaporating

• bubbles forming when two substances are mixed

• temperature remaining the same when two substances are mixed

Tags

NGSS.MS-PS1-2