const1 = 100;
const2 = 50;
deltaE1 = 8.314*77*Log[const1]
deltaE2 = 8.314*77*Log[const2]
pVap = 1;
monolayerCap1 = 300;   
monolayerCap2 = 
      100;
amtAdsorbed1 = 
        monolayerCap1*const1*
          pressure/((pVap - 
                    pressure)*(1 + (const1 - 1)*
                      pressure/pVap));
amtAdsorbed2 = 
        monolayerCap2*const2*
          pressure/((pVap - 
                    pressure)*(1 + (const2 - 1)*
                      pressure/pVap));
Plot[{amtAdsorbed1, amtAdsorbed2}, {pressure, 0, 0.6}, 
        PlotStyle -> {{RGBColor[1, 0, 0]}, {RGBColor[0, 0, 
                1]}}];

What is a "typical" value of BET intercept and monolayer capacity?

vM = 100;  
surfArea = vM/
          22400*6.022*10^23*(15*10^-20)

n = 2;
const = 100;
monolayerCap = 100;
amtAdsorbed2 = 
        monolayerCap*const*
          relP/(1 - relP)*(1 - (n + 1)*relP^n + 
                n*relP^(n + 1))/(1 + (const - 1)*relP - 
                const*relP^(n + 1));
Plot[amtAdsorbed2, {relP, 0, 1}];

molWt = 28;
density = 0.751;
MolArea = 
      4*0.866*(molWt/(4*2^0.5*6.022*10^23*density))^(2/
              3)

Clear[vM, c]
soln1 = 
      Solve[{(c - 1)/vM/c == 
            2*10^-3/(0.205 - 0.065), 1/vM/c == 
            0.2*10^-3}, {vM, c}]

vM_norm = soln1[[1, 1, 2]]/0.606
cNew = soln1[[1, 2, 2]]

deltaE = 1.987*90.1*Log[cNew]

surfaceArea = 116.2/22400*6.022*10^23*16.2*10^-20

Solution to P25.5, Atkins. See also Brunauer_1938_Paper.xlsx, as well as p. 1039 in Atkins8.

slope3 = 76.1*10^-3;
intercept3 = 0.464*10^-3;
soln3 = 
      Solve[{1/vM3/const3 == intercept3, (const3 - 1)/vM3/const3 == 
            slope3}, {vM3, const3}]
const3a = soln3[[1, 2, 2]]
vM3a = soln3[[1, 1, 2]]

Analysis of Figures 1 and 2 in Brunauer et al., 1938)... See also Brunauer_1938_Paper.xlsx. Do the numbers obtained agree with those appearing in the table(s)? Any adjustments necessary?

Clear[slope1, intercept1, const1, vM1]
slope1 = 13.13*10^-3;
intercept1 = 0.039*10^-3;
soln1 = 
      Solve[{1/vM1/const1 == intercept1, (const1 - 1)/vM1/const1 == 
            slope1}, {vM1, const1}]
const1a = soln1[[1, 2, 2]]
delE = 1.987*77*Log[const1a]

lrr3@psu.edu (09/05/07)