Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Rain_Fall on October 03, 2007, 03:44:44 AM
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Which of the following describes a physical change?
(please answer only if you are a hundred percent sure of you answer)
the answer could be more than one choice
1. An egg is fried in a skillet.
2. An overgrown lawn is manicured by mowing it with a lawn mower.
3. Because a lawn is watered and fertilized, the grass grows thicker.
4. Ice cubes form when a tray filled with water is placed in a freezer.
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I would say no. 2. You are only changing the grass physically and not chemically. Others are changed chemically.
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damn, it's wrong dude I only have one more chance to answer it correctly. Thank you though
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2 and 4 are definitely physical changes. 1 is a chemical change. I would think 3 would also be chemical.
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Doesn't a 3D lattice form from H-bonding when water freezes? would this be considered as physical change?
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Doesn't a 3D lattice form from H-bonding when water freezes? would this be considered as physical change?
Yes. It is definitely a physical change. When water freezes, the chemical composition does not change (it is still H2O).
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so why is no.2 wrong?
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so why is no.2 wrong?
It isn't, it is just not the only correct answer.
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No.2 can also involve a chemical change.
When you cut grass you break the cell walls and oxidise the contents i think.