Chlorophyll the green pigment a complex of magnesium contains 2.68 % of magnesium by weight. Calculate the number of magnesium atoms in 5 gram of the chlorophyll.

Please explain in detail.

since chlorophyll contains 2.68% Mg therefore weight

of Mg in 5g chlorophyll = 5×2.68/100 = .134 g

now Mole of Mg = weight/atomic weight

= .134/24

since 1 mole contains 6.023×10^23 particles

therefore number of atoms present

in .134/24 mole will be = (.134/24) × 6.023×10^23

=3.3628 × 10^21 atoms of Mg