Physical and Chemical Properties and Changes

Identify the following as a chemical (C) or physical property (P): sour taste

• Chemical (C)

• Physical (P)

Answer explanation

Sour taste is a characteristic of acids, which indicates a chemical property. It reflects the substance's ability to react with taste receptors, thus classifying it as a chemical property (C).

Identify the following as physical (P) or chemical (C) changes: NaCl (Table Salt) dissolves in water.

• Physical

• Chemical

Answer explanation

Dissolving NaCl in water is a physical change because the salt retains its chemical identity. The process involves a change in state from solid to aqueous, but no new substances are formed.

Identify the following as physical (P) or chemical (C) changes: Heat changes H2O to steam.

• Physical (P)

• Chemical (C)

Answer explanation

The process of heating H2O to steam is a physical change (P) because it involves a change in state from liquid to gas without altering the chemical composition of water.

Tags

NGSS.MS-PS1-4

Identify the following as physical (P) or chemical (C) changes: Baking soda reacts to vinegar.

• Physical (P)

• Chemical (C)

Answer explanation

Baking soda reacting with vinegar produces carbon dioxide gas and new substances, indicating a chemical change. Therefore, the correct classification is Chemical (C).

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Identify the following as physical (P) or chemical (C) changes: Ice melts.

• Physical (P)

• Chemical (C)

Answer explanation

Ice melting is a physical change because it involves a change in state from solid to liquid without altering the chemical composition of water. Thus, the correct choice is Physical (P).

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Identify the following as physical (P) or chemical (C) changes: Milk sours.

• Physical (P)

• Chemical (C)

Answer explanation

Milk souring is a chemical change (C) because it involves the fermentation of lactose into lactic acid, altering the chemical composition of the milk.

Tags

NGSS.MS-PS1-2

Identify the following as physical (P) or chemical (C) changes: Wood rots.

• Physical (P)

• Chemical (C)

Answer explanation

Wood rotting is a chemical change (C) because it involves the decomposition of organic material, resulting in new substances, such as gases and nutrients, rather than just a change in physical form.

Tags

NGSS.MS-PS1-2

Identify the following as physical (P) or chemical (C) changes: Pancakes cook.

• Physical (P)

• Chemical (C)

Answer explanation

Pancakes cooking is a chemical change (C) because it involves the transformation of batter into a solid form through heat, resulting in new substances like proteins and sugars reacting, which alters their chemical structure.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Identify the following as physical (P) or chemical (C) changes: Grass grows.

• Physical (P)

• Chemical (C)

Answer explanation

Grass growing is a physical change (P) because it involves growth and development without altering the chemical composition of the plant. The process is part of the plant's life cycle, not a chemical reaction.

Tags

NGSS.MS-PS1-2

Read each scenario. Decide whether a physical or chemical change has occurred.

A student removes a loaf of bread hot from the oven. The student cuts a slice off the loaf and spreads butter on it. Is this a physical or chemical change?

• Physical change

• Chemical change

Answer explanation

This is a physical change because cutting the bread and spreading butter does not alter the chemical composition of the bread or butter. The bread remains bread, and the butter remains butter.

Tags

NGSS.MS-PS1-2