4. This is the phase diagram for carbon dioxide. a) Label...

4. This is the phase diagram for carbon dioxide. a) Label the critical point and triple point. (2pts) b) What is an approximate value for the boiling point of CO2 at 70 atm? (2 pts) Pressure (atm) —> 73.0 5.11 1 -78.5 -56.4 31.1 Temperature (°C) —> Supercritical fluid Solid Liquid Gas c) Describe the phase change(s) that occur(s) when CO2 at 20 °C and 2 atm pressure is cooled down to - 100 °C. (2 pts)

Transcript

00:01 Hello, students.

00:02 So in this portion, you are given with this whole phase diagram, right? and you have to first question is to find out the critical point and the triplet point, but this whole phase diagram.

00:14 So before going to the critical point and triplet point in the diagram, we should know what is exactly the ar.

00:20 Yeah.

00:21 So when we talk about critical point specifically, what is the critical point? critical point is a point where the vapor, where the vapor, and, and, and, you know, and, the liquid and liquid are indistinguishable okay you cannot separate these both are indistinguishable this thing wish all right so you cannot separate these both vapor phase and the liquid phase they both occur simultaneously so when we talk about the triplet point okay in the triplet point what happens in the triplet point we have all the stages like vapor we should start with the solid.

01:09 Solid vapor and liquid face.

01:17 Liquid face exist.

01:22 These all coexist.

01:24 So you can simply write this as coexist at one point.

01:31 At one point.

01:32 So there if you talk about an ice, so here if you talk about water, right, the phase equilibrium of water.

01:39 So here the ice, water and vapor, they will be existing altogether.

01:44 In the equilibrium at the triplet point so now if you see the diagram over here right so in the diagram if you see here we have a point i'll mark them as we have points say we have a point of this one point first okay and then we have the second one point over we have the second point we have the second point over this one okay so one i'm naming it as a a, this is not much visible.

02:28 I'm naming this as a and this as b.

02:32 Okay.

02:32 So here if you see in the a and b, on this point a, okay, so we called it preplit point where the solid vapor and liquid they coexist.

02:42 So in this point you can see this side we have the solid state, this side we have the liquid state and this side we have the gaseous state.

02:49 So here this is the point where which exists between the all three phases.

02:54 Okay.

02:54 This side, it this side liquid and this side gas.

02:57 So we can say a is our triplet point...

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