1) Burning wood is a physical change.
2) Crushing a rock is a physical change.
3) Dissolving sugar in water is a chemical change.
4) Rusting of iron is a chemical change.
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5) Milk is a pure substance.
6) Table salt is a mixture.
7) Sugar is a pure substance.
8) Steel is a mixture.
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9) A black cup of coffee is homogeneous and pure.
10) Boiling water is: Physical Change & Physical Property
The answer which caught me off guard was #9. At first glance I thought a "black" cup of coffee implied there were no additives thus making it an homogenous and pure structure. When I double checked my answers and it stated its a homogenous and impure structure. Its impurebecause coffee has additives by the time it reaches us and our hot water. This was easy for me to accept due to the fact most items in our grocery stories involve some form of processing before arriving in our home or purchasing them at a cafe/restaurant.
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