Number of atoms of iron present in 100 g of Fe2O3 having 20% purity is

Q. One of the reactions that occurs in a blast furnace, where iron ore is converted to cast iron is as follows:
$F{e}_2{O}_3+3CO⟶2Fe+3C{O}_2$
Suppose that $1.64\times {10}^3$ kg of Fe are obtained from $2.62\times {10}^3$ kg sample $F{e}_2{O}_3$. Assuming that the reaction goes to completion, what is the percent purity of $F{e}_2{O}_3$ in the original sample (rounded to the nearest integer)?

Q. $8.33\times {10}^x$ carbon atoms are present in a diamond weighing $200$ mg and of $20$ carat purity. Then, the value of $x$ is _______. write the value in the form of x/3.

Q. Number of iron atoms present in haemoglobin molecule is

Q. Percentage purity of a sample of gold is $85\%$. How many atoms of gold are present in its $1$ gram sample? (Atomic mass of gold $=197$u).

Q. The number of iron (Fe) atoms present in a pure sample of solid iron with a mass of 10 grams is equal to- (The atomic mass of iron is 55.9) .