Question

At 1atm and 273K the volume of $N_2$ gas required to cover a sample of silica gel assuming Langmuir monolayer adsorption, is found to be $1.30c{m}^3/g$ of the gel. The area occupied by a nitrogen molecule is 0.16 ${nm}^2$. What is the surface area per gram of silica gel?

($N_A={6\times 10}^{23}$)

• A. 5.568/g
• B. 3.48/g
• C. 1.6/g
• D. None of the above

Answer 1

Answer: (A)

5.568/g

No. of molecules per gram of $N_2$ in monolayer$=\frac{6\times {10}^{23}\times 1.30}{22400}$

$=3.48\times {10}^{19}$

cross sectional area of molecule$=0.16n{m}^2$

$=1.6\times {10}^{-19}{m}^2$

Surface area covered per gram of silica gel= Surface area covered per g of $N_2=3.48\times {10}^{19}\times 1.6\times {10}^{-19}$

$=5.568m^2$.