Chemical Changes

Which of the following best describes a chemical change?

• Change in shape

• Change in color without new substance

• Formation of a new substance

• Change in size

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The production of a gas is evidence of—

• Physical change

• Chemical change

• Melting

• Dissolving

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

In the law of conservation of mass, the total mass before and after a chemical change—

• Stays the same

• Increases

• Decreases

• Doubles

Tags

NGSS.MS-PS1-5

When hydrochloric acid reacts with calcite and bubbles form, it indicates—

• A. A new gas formed (chemical change)

• B. A phase change

• C. A cooling effect

• D. Dissolving sugar

Tags

NGSS.MS-PS1-2

A physical change differs from a chemical change in that:

• a physical change does not alter the substance's chemical composition, while a chemical change does

• a physical change always produces a new substance, while a chemical change does not

• a chemical change is always reversible, while a physical change is not

• a chemical change only affects the appearance, while a physical change changes the substance itself

The total mass in a chemical reaction:

• remains the same

• increases

• decreases

• disappears

Tags

NGSS.MS-PS1-5

Cutting grass is considered a physical change because:

• it changes the appearance but not the chemical composition of the grass.

• it creates a new substance from the grass.

• it involves a chemical reaction with the air.

• it changes the color of the grass permanently.

A student paints two colors together and makes green paint. Why is this NOT a chemical change?

• Because no new substance is formed

• Because the paint dries quickly

• Because the colors are both liquids

• Because the paint is green

Tags

NGSS.MS-PS1-2

A clear solution turns cloudy after mixing two liquids and a solid appears at the bottom. What formed?

• Precipitate

• Gas

• Vapor

• Ice

Tags

NGSS.MS-PS1-2

Which is NOT an example of a chemical change?

• Iron rusting

• Cake baking

• Ice melting

• Burning wood

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5