a) An iron nail is attracted to a magnet.


b) Water boils at 78°C on top of a 18,500 ft.
mountain.
c) A silver spoon tarnishes in air.
d) Rainwater in industrialized regions of the
world tends to be acidic.
e) The helium in a balloon tends to leak out
after a few hours.
f.) Rubber objects tend to disintegrate in a
smog-filled environment. Chemical or physical change