Two phase monolayer

To determine the two-dimensional vapour pressure in a monolayer of myristic add on water. 

The spreading-pressure of mjnistic add CuHjj.COjH on water has been measured at 14.5 C by Adam and Jessop (Proc. Roy. Soc. 1926, 110, 423, and private communication from Adam to Wolfenden), Some of their measurements are given in table 1. The first column gives the mass of myristic acid, the second column the length of the film, and the third column the force on the float. The width of the trough was 14.0cm and the efiective width of the barrier was 12.33 cm. 

Multipljdng the length of the film by its width and dividing by the mass of mjnristic acid we obtain the area per unit mass, which we then convert into area A per molecule. Dividing the force on the float by its effective length we obtain the spreading pressure p. 

We find that p is sensibly constant from A = 50 A to at least A = 500 A . We conclude that over this region there are two surface phases in equilibrium at a spreading pressme (two-dimensional vapour pressure ) of 0.20 d3me cm . 

To calculate the second-order rate constant for the dimerization of butadiene in the gas phase. 

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