Question

an enzyme contains 18.3% Fe by mass . if molarmass of Fe is 56 g , then find out how many number of Fe atoms are present in 10 g of enzyme

Answer 1

Given % by mass of Fe in enzyme = 18.3%
Therefore we can say that 100g of enzyme contains 18.3g of Fe.
So 10g of enzyme will contain (18.3*10)/100 = 1.83g Fe.

Now Moles of Fe in 10g enzyme = 1.83/56 = 0.032 moles of Fe.
Then no. of Fe atoms in 10g enzyme = 0.032*Avogadro No. = 0.032*6.02*10^23 = 1.926*10^22 atoms of Fe.