Question

what do these two changes have in common?
a copper statue turning green
grilling a hamburger
select all that apply.
both are only physical changes.
both are chemical changes.
both are caused by heating.
both are caused by cooling.
submit
work it out
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Explanation:

1. Analyze the first change (copper statue turning green): Copper reacts with substances in the environment (like oxygen, moisture, carbon dioxide) to form a new compound (patina, usually copper carbonate or hydroxide), which is a chemical change. It's not caused by heating or cooling directly in the typical sense of temperature change for this reaction.
2. Analyze the second change (grilling a hamburger): Grilling involves cooking, where the meat undergoes chemical reactions (like Maillard reaction, breakdown of proteins and fats) to form new substances, so it's a chemical change. Grilling is caused by heating.
3. Evaluate the options:

• "Both are only physical changes": Incorrect, as both involve chemical reactions (new substances formed).
• "Both are chemical changes": Correct, as both result in new substances (patina for copper, cooked meat with new chemical structures from grilling).
• "Both are caused by heating": Incorrect, the copper statue turning green is not caused by heating (it's a reaction with environmental factors over time, not direct heating like grilling).
• "Both are caused by cooling": Incorrect, neither change is caused by cooling.

Answer:

B. Both are chemical changes