For which of the following processes would Delta S have a negative value

c is the answer because when something is left after something evaporates that shows the chemical change.

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72

im pretty sure its b