The volume of nitrogen gas `Vm` (at STP) reqired to cover a sample of silica gel with a monomolecular layer is `129cm^(3)g^(-1)` of gel. Calculate the surface area per gram of the gel if each nitrogen molecule occupies `16.23xx10^(-20)m^(2)` .

Explanation

To solve the problem, we will follow these steps:

### Step 1: Calculate the number of nitrogen molecules in 129 cm³ of nitrogen gas at STP.

At STP (Standard Temperature and Pressure), 1 mole of any gas occupies 22,400 mL. Therefore, we can use the following relationship to find the number of moles in 129 cm³ of nitrogen gas:

\[
\text{Number of moles of } N_2 = \frac{\text{Volume of } N_2}{\text{Molar volume at STP}} = \frac{129 \, \text{cm}^3}{22400 \, \text{cm}^3/mol}
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