Benzene has a melting point of 5.53 °C and a boiling point of 80....

Question

Benzene has a melting point of 5.53 °C and a boiling point of 80.09 °C at atmospheric pressure. Its density is0.8787 g>cm3 when liquid and 0.899 g>cm3 when solid; it has Tc = 289.01 °C, Pc = 48.34 atm, Tt = 5.52 °C, and Pt = 0.0473 atm. Starting from a point at 200 K and
66.5 atm, trace the following path on a phase diagram. (1) First, increase T to 585 K while keeping P constant.
(2) Next, decrease P to 38.5 atm while keeping T constant.
(3) Then, decrease T to 278.66 K while keeping P constant.
(4) Finally, decrease P to 0.0025 atm while keeping T
constant.
What is your starting phase, and what is your final phase?

Accepted Answer

Hello. Everyone in this video. We want to go ahead and construct our own phase diagram. So we're given some information here that helped guide us to do So we're also given the certain steps here to identify the starting phase and final phase of iodine. So I to just go ahead and verse drought the skeletal phase diagram. So you know that our Y axis that's going to be our pressure. Of course that's in units of A. T. M. And then our X axis here, that's going to be our temperature and degrees Celsius being our units. Now we scroll up, We can find some information about our triple point. It says that our triple point is at 114°C and at .1-80 M. Let's go ahead. Mark that down. So we'll put our triple point maybe over here. And we say that this is going to be 100 and 14 degrees Celsius. And then our pressure here, that's going to be 0.12. Again, that's our triple point. So then we can go ahead and make our skeletal phase diagram and then we have lines like towards the right. All right, So we know that this is a solid liquid and then gas. So we see here that the solid to liquid line. So this one right here is leading towards the right because solid is more dense than the liquid. Alright, so for our starting point of this material, every scroll up, this is the starting point is at 75 degrees Celsius and at five A. T. M. So that's approximately let's see. So if the temperature is 75 is definitely lower than our triple point and then for our five A team that's higher than our triple point. So maybe about over here will mark the first starting point right over here. The starting. Alright then for step one is when the changes are made. So step one, the changes are made is when the temperature is being increased to 200 degrees Celsius, A constant pressure. The pressure remains at five A. T. M. But the temperature is going up. So it goes this point we'll go ahead and go towards the right, so go ahead and put this in black the transition. So we're going to maybe let's see if we're going to 200 degrees. It'll be approximately right over here. So put this in a green dot and I'll star that here as well. And then for step two says, the pressure's being decreased. 2.5 A. T. M. At a constant temperature. The temperature is still at 200 degrees Celsius. But the pressure is dropping 2.5 for dropping it means that the transition here is just going down. So have it go right over here to actually make this a blue dot. Put a blue star here for step two. Alright, Step three is as the temperature is being decreased 215 degrees Celsius at a constant pressure. The pressure is still at 2150.5 A. T. M. But the temperature's going back. So basically the transition here is going towards the left, so have it over here after 15 is really close to our triple point. So just do that. Let's make this point purple and store that as well. And the last transition. So for step four is that the pressure is being decreased, 2.50 A. T. M. And a constant temperature. The temperature is still at 115 degrees Celsius, but the pressure is going down is going to be below our triple points. So it's approximately right over here and then we can go ahead and go back to black or red and this is our final point. So taking a look at this diagram that we just made them for our starting is right over here and this is in its solid state so we can go and work this out for answer. So starting fares that's a solid. And then for the final phase, if we have done everything correctly, we see the final point being here and that's in its gaseous phase. So the final phase is going to be a gas. So this right here is going to move my final answer for this problem

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