Mass Transfer Question

Predict the diffusion coefficient for nitrogen through a mixture containing 50% hydrogen, 30% ammonia, 15% nitrogen, and 5% water at 25°C and 1 atm. This was my thought process on which equation to start with but do I assume I'm dealing with water and ammonia in a gas phase? Would this even be a correct equation to use?.

Assumptions: Stagnant mixture

$$D_{AM} = \frac {1-x_A}{\sum_{i=1}^n \frac{x_i}{D_{Ai}}} = \frac{1-x_A}{\frac{x_B}{D_{AB}}+\frac{x_C}{D_{AC}}+\frac{x_D}{D_{AD}}}$$ $A=\text{N}_2$

$B=\text{H}_2$

$C=\text{NH}_3$

$D=\text{H}_2\text{O}$

• I edited your question to change from the photo to mathjax formulas. Double check it to make sure I got everything right. Feb 1, 2016 at 12:59

$$D'_{A} = \frac {1-y_A}{\sum_{i=1}^n \frac{y_i}{D_{Ai}}} = \frac{1-y_A}{\frac{y_B}{D_{AB}}+\frac{y_C}{D_{AC}}+\frac{y_D}{D_{AD}}}$$ $A=\text{N}_2$
$B=\text{H}_2$
$C=\text{NH}_3$
$D=\text{H}_2\text{O}$
Your textbook might be a little different, but I don't like adding subscripts to denote mixtures. I noticed your equation has $D_{AM}$. I changed this to D prime of component A, $D'_A$.