[Rain_Fall]

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.

[djdato]

I would say no. 2. You are only changing the grass physically and not chemically. Others are changed chemically.

[Rain_Fall]

damn, it's wrong dude I only have one more chance to answer it correctly. Thank you though

[Sev]

2 and 4 are definitely physical changes.  1 is a chemical change.  I would think 3 would also be chemical.

[djdato]

Doesn't a 3D lattice form from H-bonding when water freezes? would this be considered as physical change?

[Sev]

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).

[djdato]

so why is no.2 wrong?

[Sev]

so why is no.2 wrong?

It isn't, it is just not the only correct answer.

[DrCMS]

No.2 can also involve a chemical change.
When you cut grass you break the cell walls and oxidise the contents i think.