What surface area can 2 grains of Platinum cover if the surface is one atom thick

Question

anonymous · Answer

2 grains Pt  →→ 0.01mole 
If you want to solve this problem, you must know that the radius of Pt is 135 pm (1.35A)
The surface area could be 
[1.35*10^(-10)](^2) * π * 0.01 * 6.02 * 10(^23)   square meter    (*APPROX.)

unklerhaukus · Answer

$$2.00[\text{gr}][\text{Pt}]$$$$=2.00[\text{gr}][\text{Pt}]\times\frac{0.0648[\text{g}]}{[\text{gr}]}\times\frac{1[\text{mole}]}{195[\text g][\text {Pt}]}$$$$=6.65\times10^{-4}[\text{mole}]$$$$=6.65\times10^{-4}[\text{mole}]\times6.022\times10^{23}[\text{atom}/\text{mole}]$$$$=4.00\times10^{20}[\text{atom}]$$$$=4.00\times10^{20}[\text{atom}]\times\pi(1.35[\text Å])^2[\text m^2/\text{atom}]$$$$=22.9[\text m^2]$$