(a)Calculate the number of molecules of SO² present in 44g of it.

(b)If one mole of oxygen atoms weigh 16 grams find the mass of one atom of oxygen (in grams).

Urgent i had test tomorrow

To find the number of molecules, we need to first find the number of moles of SO₂ present in 44g of the compound. To do this we need to use the formula
Step 1  Moles = $\frac{mass of S{O}_2}{molar mass of SO2}$
Molar mass of SO₂ =  atomic mass of S +  2 X atomic mass of O
  =  32  amu (g/mol) +  2 X 16 amu (g/mol)
  =  32 + 32 = 64 g/mol
Therefore moles of SO₂ =  44/64 =  mol
Step2: Use Avogadro number to convert moles into the number of molecules
  Number of SO₂ molecules =  number of moles  X  Avogadro number
   =  0.6875 mol  X  (6.022  X  10²³) molecules/mol= 4.14X 10²³ molecules

2.  To find mass of 1 oxygen atom,  we divide the mass of 1 mole of oxygen atom by number of oxygen atoms in one mole which equals Avogadro number
 
1 mole of O atoms contains = 6.022 X 10²³ atoms of O
1 mole or 6.022 X 10²³ atoms of O have a mass of 16g
Mass of one atom of O  =  $\frac{16}{6.022 \times {10}^{23}}$ = 2.66 X 10^-23g