Answer to Question #314527 in General Chemistry for Nel

Question

Visualize a substance with the following points on the phase diagram: a triple point at 0.5 atm and 150 K; a normal melting point at 175 K; a normal boiling point at 350 K; and a critical point at 2.0 atm and 450 K. The solid liquid line is “normal” (meaning positive sloping). For this, complete the following:

a) Roughly sketch the phase diagram, using units of atmosphere and Kelvin. Label the area 1, 2, and 3, and points T and C on the diagram.

b) Describe what one would see at pressures and temperatures above 2.0 atm and 450 K.

c) Describe the phase changes from 50 K to 250 K at 1.5 atm.

d) What exists in a system that is at 1 atm and 350 K?

e) What exists in a system that is at 1 atm and 175 K?

Answer 1

we've sketched out a phase diagram here. We started with the liquid vapor pressure of six atmospheres and 550. So, that's this point right here. And the triple points at five atmospheres in 3 50. So that's this point right here, the solid phase is more dense. That's why this line slants to the right, okay, So we've got a sketch there, we've got our solid liquid and vapor areas. So we're gonna try to use this now to estimate the temperature When you're at 6.3 ATM. So 6.3, it's just a little bit above here, so, we're gonna come over and we're gonna come down and I'm gonna guess We're about 600°C. Again, this is very rounded because we're not really to scale and we're not using a graph paper. All right. And then finally, what happens when we're at a constant pressure of four atmospheres, Then we go from 400 to 100. So, we're somewhere around here. All right. Mhm. And we're gonna drop down to 100, so we're gonna come down over here. So we're going from a vapor to a solid. And that process is called deposition.