2009 DAT #66 physical change

[VDR]

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I am a bit confused on why this is the correct answer.

Q: each of the following is an example of a chemical change except one. which one is the exception?

a. hydrogen peroxide decomposing to form molecular oxygen and water.
b. methanol burning in air with a colorless flame.
c. aluminum foil melting at 660 C
d. hydrochloric acid neutralizing a solution of sodium hydroxide
e. iron metal rusting

the correct answer is C. (aluminum foil melting at 660).

Thanks

 

[FROGGBUSTER]

I am a bit confused on why this is the correct answer.

Q: each of the following is an example of a chemical change except one. which one is the exception?

a. hydrogen peroxide decomposing to form molecular oxygen and water.
b. methanol burning in air with a colorless flame.
c. aluminum foil melting at 660 C
d. hydrochloric acid neutralizing a solution of sodium hydroxide
e. iron metal rusting

the correct answer is C. (aluminum foil melting at 660).

Thanks

If something like ice melts, do you know why that's a physical change and not a chemical one? A physical change means nothing happens to the molecules themselves. You're not breaking covalent bonds. In the case of melting, all that's happening is that solid --> liquid, which is just furthering the intermolecular forces.

 

[VDR]

Thanks. Makes sense. I didn't focus on chemical vs. physical.