How many water molecules in a #0.90*g# mass of water?
The mass of one mole of water is
of water. One mole of water contains Avagadro's constant, ie,
We find the molar quantity.....and get
And we know that there are
And so we take the product......
(i) how many oxygen atoms in this molar quantity; and (ii) how many hydrogen atoms......?
Number of molecules = Mass in grams