Chemical vs Physical Changes Flashcards
Grade 5 · Science · Flashcards
Review key terms and examples to master the difference between chemical and physical changes.
Flashcards
- Physical Change
- A change that alters the size, shape, or state of matter WITHOUT creating a new substance. Examples: cutting, bending, melting, dissolving.
- Chemical Change
- A change that produces one or more new substances with different properties. Examples: burning, rusting, cooking.
- Signs of a Chemical Change
- Gas bubbles, color change, precipitate forming, heat/light released, or an unusual smell — all suggest new substances formed.
- Precipitate
- A solid that forms when two liquids are mixed during a chemical reaction, sinking to the bottom of the container.
- Reversible vs Irreversible
- Physical changes are usually reversible (ice melts and can refreeze). Chemical changes are usually irreversible (ash cannot become wood again).
- Burning Paper
- Chemical change — paper reacts with oxygen to form ash, carbon dioxide, and water vapor; entirely new substances result.
- Melting Chocolate
- Physical change — chocolate changes state from solid to liquid, but the chocolate molecules remain the same.
- Rusting Iron
- Chemical change — iron + oxygen + water → iron oxide (rust), which has completely different properties than iron.
- Mixing Baking Soda and Vinegar
- Chemical change — produces carbon dioxide gas (bubbles), water, and a salt; new substances are formed.
- Cutting Fruit
- Physical change — shape and size change, but the fruit material itself is unchanged.
- Reactant
- The starting substance(s) that enter a chemical reaction before any change occurs.
- Product
- The new substance(s) formed after a chemical reaction takes place.
- Law of Conservation of Mass
- In any chemical or physical change, matter is neither created nor destroyed — the total mass of reactants equals the total mass of products.
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