If you have 5.00 x 10^24 molecules of water how many moles of water would you
have?

8.31moles of H2O

Explanation:

Avogadro's hypothesis gives us an excellent understanding that 1mole of any substance contains 6.02x10^23 molecules. This means that 1mole H2O also contains 6.02x10^23 molecules.

Now, if 1 mole of H2O contains 6.02x10^23 molecules

Therefore, Xmol of H2O will contain 5.00x10^24 molecules i.e

Xmol of H2O = (5.00x10^24)/6.02x10^23 = 8.31moles of H2O

c (diamond),

sio2 (quartz)