Question

If number of molecules in a sample of sulphur dioxide is 3.011×1023 then calculate the number of oxygen atoms in it.

Answer 1

Sulphur dioxide is SO2
According to mole concept:
1 mole of a molecule = 6.023 x 10^23 molecules
therfore:
1 mole of SO2 molecule = 6.023 x 10^23 molecules of SO2

Number of moles = Number of molecules/Avogadros number
Avogadros number = 6.023 x 10^23
Number of molecules of SO2 = 3.011 x 10^23
Moles of SO2 = Number of molecules/Avogadros number
= 3.011 x 10^23/6.023 x 10^23 = 0.5 mole
Now
1 mole of SO2 contains 1 mole of Satoms, and 2 moles of Oxygen atoms
1 mole of SO2 = 2 moles of Oxygen atom
therfore, moles of Oxygen = 2 x moles of SO2 = 2 x 0.5 = 1 mole
There is 1 mole of Oxygen atom in given sample of SO2

as 1 mole of atom = 6.023 x 10^23 atoms
therfore 1 mole of O atom = 6.023 x 10^23 oxygen atoms
Hence SO2 contains 6.023 x 10^23 Oxygen atoms