[tortoise]

Sulfur molecules exist under various conditions as S₈, S₆,
S₄, S₂, and S.
(a) Is the mass of one mole of each of these molecules the same?
(b) Is the number of molecules in one mole of each of these molecules the same?
(c) Is the mass of sulfur in one mole of each of these molecules the same?
(d) Is the number of atoms of sulfur  in one mole of each of these molecules the same?

(a) the same, = ?
(b) not the same
(c) the same, = 32g ?
(d) not the same

I am not sure about my answers. What is the difference between (a) and (c)?

Please help me.
Thanks in advance.

[Sev]

a) no (eg. a mole of S₄ would be twice the mass of a mole of S₂)
b) yes.  Each will have Avagadro's number of molecules.
c) atomic mass will remain the same.
d) no.  eg. S₄ will contain twice the number of S₂

[AWK]

c) atomic mass will remain the same.

But question do not concern  the atomic mass

[tortoise]

What about my answer, AWK?

[AWK]

Only your answer for d is correct.
Sev gave correct answers for a and b

[tortoise]

many thanks! but, you left (c) for me to be crazy with   
Can you give an answer to it?

Thanks.

[AWK]

The answer is evident - just different than yours - mass of sulfur in 1 mole of S₆ must be different than in 1 mole of S₈

[gonzo]

It might be easier for you if you remember that a mole is a specific number (Avogadro's number), so in case of c):

- is the mass of a sulfur molecule S2 the same as S4? No, the S4 is twice as big, so the mass is twice as big. So whether we have one of each molecules or 100 of each molecules we know one is twice as large mass as the other. In this case we have a mole of each molecule (a really large amount, 6.022x10^23), but it's the same amount of molecules in each group, so the bigger molecules with the bigger mass still have twice the mass in comparison to the smaller ones.

I remember being really confused about moles when I needed to use them, hopefully I haven't fed you wrong information (please someone correct me if that's the case)!