What Are the Partial Pressures and Total Pressure in a Reaction Mixture?

[Coffeepower]

[SOLVED] PCHEM/Partial Pressures Question

Problem Statement:
A vessel of volume 22.4dm^{}3 contains 2.0 mol H_{}2 and 1.0 mol of N_{}2 at 273.15K initially. All the H_{}2reacted with sufficient N_{}2 to form NH_{}3. Calculate the partial pressures and the total pressure of the final mixture.

Variables and Magnitudes:
V = 22.4dm^{}3
T = 273.15K
n_{}H_{}2= 2.0 mol
n_{}N_{}2= 1.0 mol

First Attempt:
2H_{}2+N_{}2\rightarrowNH_{}3
It takes 1.5 mol of H_{}2 to make 1 mol of NH_{}3 so I was thinking that I should say that:

p_{}H_{}2 = p_{}total*X_{}H_{}2 = ?

We would need to calculate the total pressure first for this.

I need a place to start this problem. I just can't put my finger on it.

 

[Coffeepower]

After working on the problem some more; I found that there is a simple way to do the problem. Simply find the mole fractions with the number of moles given and calculate the total pressure with PV = nRT for 3 moles, and 22.4dm^3.

Not much more to it than that. The solution in the book matches up.