Physical and Chemical Changes

Define physical change.

Define chemical change.

State one sign that a chemical change may have occurred.

Why is melting ice a physical change?

Why is burning paper a chemical change?

Explain why a colour change alone is not always enough evidence of a chemical reaction.

What does gas production suggest during a reaction?

Classify dissolving sugar in water as physical or chemical and justify your answer.

What is meant by a new substance forming?

Give one example of an exothermic or endothermic change.

Compare physical and chemical changes using particle arrangement, reversibility and formation of new substances.

A student mixes two clear liquids and bubbles form. Explain what this evidence could suggest and what extra evidence would strengthen the conclusion.

Explain why rusting iron is a chemical change but cutting iron into smaller pieces is a physical change.

Describe a simple investigation that could test whether a change produced a new substance.

Evaluate the claim, “If a change can be reversed, it must be physical.” Include an example or limitation.

Explain the difference between dissolving, melting and reacting using particle ideas.

Use observations to classify three changes: evaporating water, burning fuel and mixing sand with salt.

Describe how temperature change can be evidence in chemical reactions, but also why it must be interpreted carefully.

Write a table comparing at least four examples of physical and chemical changes with evidence for each classification.

Write a full explanation of how scientists use multiple observations to decide whether a chemical reaction has occurred.