Physical and Chemical Changes

A substance X is said to have undergone a chemical change. What observations imply a chemical change in substance X?

• The color of X would change.

• The phase of X would be different.

• Substance X would have a different temperature.

• The shape and texture of X would change.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of these must occur when a substance goes through a chemical change?

• The substance gets larger.

• The substance changes phases.

• The substance changes shape.

• The substance forms a new substance.

Tags

NGSS.MS-PS1-2

Two substances, A and B, react to form a third substance, C. Which is correct about this chemical reaction?

• A and C have the same appearance.

• A, B, and C are in the same phase.

• A has the same smell as C.

• A and C have different chemical compositions.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

NGSS.MS-PS1-1

What are the correct conclusions about the products of all chemical changes?

• They have similar physical properties of those of the reactants.

• They have similar molecular formula to that of the reactants.

• They have a different chemical composition from the reactants.

• They are formed based on a balanced chemical equation.

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NGSS.HS-PS1-7

Which describes only a physical change?

• baking a cake

• frying an egg

• burning a piece of toast

• squeezing the juice from fruit

Which part of digestion is mainly a chemical change?

• Teeth break food into small pieces.

• Throat muscles push food toward the stomach.

• Stomach acids dissolve food into nutrients.

• Intestinal cells transport nutrients into the blood.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A chemical change happens when

• glass breaks into pieces.

• dough bakes in an oven.

• ice cream melts into a liquid.

• electricity flows through a wire.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which statement BEST describes the formation of rust.

• Rust results from a physical mixing of iron with water.

• Rust forms from a chemical breakdown of old metal.

• Rust results from a chemical reaction between iron and water.

• Rust forms from a physical change when wind blows against metal.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of these is an example of a chemical change.

• Iron changes color when heated.

• Gas bubbles form in boiling water.

• Solid wax forms when melted wax falls on ice.

• A gas forms when vinegar and baking soda are combined.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

10 grams of a white-colored solid was heated over a burner. At the end of the reaction, it become hot and changed into a brown-colored solid. Select the statements that explain why the reaction involved a chemical change.

• The state of the substance changed.

• The color of the substance changed.

• The white solid changed to a new substance.

• The temperature of the substance increased.

• The mass of the substance remained the same.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4