Chemical and Physical Changes

What is a chemical change?

• A process where substances combine or break apart to form new substances with different properties.

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

• A reaction that only involves the rearrangement of atoms without forming new substances.

• A process that only occurs at high temperatures and pressures.

What is rusting an example of?

• A physical change

• A chemical change

• A biological change

• An environmental change

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 occurs only at high temperatures.

• A change that can be reversed without any external influence.

What happens to water when it is heated to steam?

• It undergoes a chemical change.

• It remains in liquid form.

• It undergoes a physical change.

• It freezes into ice.

Give an example of a chemical change.

• Burning wood is an example of a chemical change.

• Melting ice is an example of a chemical change.

• Dissolving sugar in water is an example of a chemical change.

• Boiling water is an example of a chemical change.

What is the difference between a chemical change and a physical change?

• A chemical change does not result in new substances, while a physical change does change the substance's chemical identity.

• A chemical change results in new substances, while a physical change does not change the substance's chemical identity.

• A chemical change is reversible, while a physical change is irreversible.

• A chemical change occurs only at high temperatures, while a physical change occurs at low temperatures.

What happens to a substance's molecules during a physical change?

• The molecules are destroyed and new ones are formed.

• The arrangement of molecules may change, but the molecules themselves remain the same.

• The molecules change into a different substance entirely.

• The molecules become larger and heavier.

How can you tell if a chemical change has occurred when cooking?

• A change in color, the release of gas, or the formation of a new odor.

• The food becomes colder than before.

• The food retains its original color and smell.

• The food cooks faster than usual.

Give an example of a physical change.

• Breaking a glass is an example of a physical change.

• Burning wood is an example of a physical change.

• Dissolving sugar in water is an example of a physical change.

• Rusting of iron is an example of a physical change.

What are some indicators of a chemical change?

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

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

• Color change, change in state, change in pressure, and change in concentration.

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