- #1

greisen

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I am to calculate the hydrostatic pressure difference - given by the

\Delta P = n*f/A

where f = 0.4 kcal/mol/Å. The unit cell has the dimension 23Å x 19.9Å x 30.4 Å and the number of water molecules are 5.4 Å in the z-direction with a molar volume of 55.5 mol/l.

I start by calculating the moles of water

n = 23Å*19.9Å*5.4Å*55.5 mol/l 1000 l/Å^3 = 1.37*10^-19 mol

Than I assume that the force is acting on the 5.4Å depth of water which gives a pressure of

\Delta P = 5.4Å*0.4 kcal/mol/Å*1.37*10^-19 mol /(23*10^-10*19.9*10¯10)m² = 6.47*10^-18 kcal/m^2

It seems a little strange and how to convert into Pascal? Any help or comments appreciated. Thanks in advance