Learn to distinguish physical changes from chemical changes, and identify signs that a chemical reaction has occurred.
A physical change alters the form or appearance of a substance without creating a new substance, and is usually reversible.
Is melting butter a physical or chemical change?
Physical change, since it can be reversed by cooling, and no new substance forms
Is tearing a piece of paper a physical or chemical change?
Physical change
A chemical change creates one or more new substances, often shown by signs like gas bubbles, a colour change, or heat being released or absorbed.
What sign of a chemical change occurs when you mix vinegar and baking soda?
Gas bubbles form (carbon dioxide is released)
Is burning paper a physical or chemical change? What signs show this?
Chemical change; signs include the paper turning to ash and smoke, which are new substances that can't be turned back into paper
1. Is freezing water a physical or chemical change?
2. Is rusting of iron a physical or chemical change?
3. Name one sign that a chemical change has occurred.
4. Is dissolving sugar in water a physical or chemical change?
5. Why are chemical changes usually harder to reverse than physical changes?
Great work finishing every chapter. Onwards to new challenges!
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