Question

Find:-
a) the mass of one atom of oxygen.
b)the mass of one molecule of oxygen.
c)the mass of one mole of oxygen gas.
d) the mass of one ion of oxygen.
e) the number of atoms in one mole of oxygen molecule

Answer 1

a) $Themassof1atom=\frac{gramatomicmassofatom}{6.022\times {10}^{23}}$

So, $themassof1oxygenatom=\frac{gramatomicmassofoxygen}{6.022\times {10}^{23}}=\frac{16g}{6.022\times {10}^{23}}$

$=2.66\times {10}^{23}$

b). Mass of one Oxygen atom = 16 amu.

1 molecule of Oxygen contains 2 atoms of Oxygen.

Thus, Mass of one molecule of oxygen = 2x16 = 32 amu.
c) To calculate the mass of 1 mole of oxygen gas
Given,
1 mole of oxygen gas

To calculate the mass,

$Mass=No.ofmole\times molarmass$

$Massofoxygen=1\times 32=32g$

d) 1 mol of $O^{2-}$ = 16g
$1moleof{O}^{2-}=6.22\times {10}^{23}{O}^{2-}$
Therefore,
$6.22\times {10}^{23}{O}^{2-}=16g$
So, $massof1O^{2-}ion=\frac{16}{6.22\times {10}^{23}}=2.6569\times {10}^{-23}g\approx 3\times {10}^{-23}g$

e) $1moleofoxygenmolecule==6.022\times {10}^{23}$

$Numberofoxygenmolecule=\frac{1}{2}\times Numberofoxygenatoms$
$\therefore 6.022\times {10}^{23}=\frac{1}{2}\times Numberofoxygenatoms$
$Numberofoxygenatoms=2\times 6.022\times {10}^{23}$
$Numberofoxygenatoms=12,044\times {10}^{23}permoleofoxygenmolecule$