To determine whether the evidence supports a physical or chemical change, we can analyze each piece of evidence provided:
Evidence of a Physical Change:
- A balloon is much smaller after letting the air out. - This indicates a change in volume but not the substance itself; thus, it is a physical change.
- There is a liquid substance in a pot after putting in a chunk of butter. - This suggests the melting of butter, which is a physical change as the chemical composition remains the same.
Evidence of a Chemical Change:
- Ash is present after a bonfire. - The formation of ash from burning indicates a chemical change as new substances are created (e.g., carbon dioxide, water, and ash).
- There is a sour-smelling liquid present in a cup of milk that was left on the counter for 3 days. - The sour smell is due to the fermentation of the milk, indicating a chemical change (bacterial growth and production of lactic acid).
- There is a loud sound after a firework explodes in the air. - The explosion involves a chemical reaction, producing gases and heat; therefore, it is a chemical change.
- There is a brown banana on the counter that was originally yellow. - The browning of the banana indicates a chemical reaction (oxidation), signaling a chemical change.
In summary:
- Physical Changes: Balloon deflating, chunk of butter melting.
- Chemical Changes: Ash from bonfire, sour milk, firework explosion, browning banana.
Overall, the evidence clearly distinguishes between physical and chemical changes based on the nature of the changes and the properties involved.
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