Physical and Chemical Changes

Give an example of a physical change.

• Ice melting into water.

• Burning wood to ash.

• Rust forming on iron.

• Cooking an egg.

What is a physical change?

• A change that alters the chemical composition of a substance.

• A change that affects one or more physical properties of a substance without altering its chemical composition.

• A change that only occurs at high temperatures.

• A change that results in the formation of a new substance.

What is a chemical change?

• A change that results in the formation of new chemical substances.

• A physical change that does not alter the chemical composition.

• A process that only involves the change of state of matter.

• A change that can be easily reversed without any chemical reaction.

What are some indicators of a physical change?

• Changes in color and odor

• Changes in state (solid, liquid, gas), shape, size, or texture without a change in chemical composition

• Production of gas or bubbles

• Formation of a precipitate

Can a chemical change be reversed?

• Yes, all chemical changes can be reversed.

• Most chemical changes are not easily reversible.

• Only physical changes can be reversed.

• Some chemical changes can be reversed with the right conditions.

Can a physical change be reversed?

• Yes, all physical changes can be reversed.

• Many physical changes can be reversed, such as freezing and melting.

• No, physical changes are always permanent.

• Only some physical changes can be reversed, but most cannot.

What happens to the chemical composition during a physical change?

• The chemical composition changes completely.

• The chemical composition remains the same; only its physical properties change.

• The chemical composition becomes more complex.

• The chemical composition is destroyed.

What happens to the chemical composition during a chemical change?

• The chemical composition remains unchanged.

• The chemical composition changes, resulting in the formation of new substances.

• The chemical composition is temporarily altered but returns to its original state.

• The chemical composition is enhanced by the addition of new elements.

What are some indicators of a chemical change?

• Color change, temperature change, gas production, and the formation of a precipitate.

• Change in mass, change in volume, change in shape, and change in density.

• Color change, sound production, change in pressure, and change in state.

• Change in smell, change in texture, change in color, and change in temperature.

Is separating sand and gravel a physical or chemical change?

• A physical change because it involves a physical process of sorting without changing the substances themselves.

• A chemical change because it alters the chemical composition of the materials.

• A physical change because it involves heating the materials.

• A chemical change because it requires a reaction between the substances.