# CHEM: Triple point Temp and Pressure

1. Nov 17, 2008

### ktmtalker

1. The problem statement, all variables and given/known data
I need to calculate the temperature and pressure at the triple point. natural log of pressure of the liquid/solid: lnp(solid)= 29.411-(5893.5K/T) lnp(liquid)=22.254-(3479.9K/T). The compound is uranium hexafluoride, MW= 352.02. I do not believe the actual molecule matters to much, just the weight. pressure is in Pa.

2. Relevant equations
lnp(solid)= 29.411-(5893.5K/T)
lnp(liquid)=22.254-(3479.9K/T)

3. The attempt at a solution
3. The attempt at a solution
I used P= 1 atm -->101.325kPa, and using the lnp(solid) equation determined a temperature. I then used that same temp in the lnp(liquid) to solve the other lnp equation. It did not go well. I am unsure on how to relate these two equations to the triple point. I should be able to grind through the math when I know how to relate it all.

2. Nov 26, 2016

### Bystander

When one "assumes" one atmosphere, one makes a big mistake. You have two equations. Do they intersect? What is the relationship of that intersection to the triple-point?