Question

9. The phase diagram for Xenon is provided opposite Liquid What phase change(s) occur as Xenon is cooled from room temperature to -150°C at 2 atm pressure 100 Solid 10 Deposition only Condensation then Freezing а) b) Gas c) Melting then Vaporisation 0.1 d) Condensation then Sublimation 0.01 Sublimation only е) -180 -120 -60 0 60 Temperature (C) 10. A schematic phase diagram is shown below. The temperature and pressure defining the (solid,liquid,gas) triple point (Tip,Pp) and the critical point (Te,P) are indicated The triple points are given for a number of substances in the Table below. In each of the substances, the solid is more dense than the liquid. (TоР liquid Triple Point TipTriple Point Psp (K) 68.1 Substance solid (atm) 0.152 СО CH4 NH3 90.7 0.118 gas (Tsp.Ptp) 195.4 0.0598 Which answer correctly identifies the substances that are solids at 100 K and 0.1 atm? Temperature Со All of them а) d) b) CH4 е) None of them c) NH3 Pressure Pressure (atm)

Answer 1

9. (B) Condensation then freezing. As shown in the graph of 9 initial position is point A and final position is B. When we decreases the pressure at constant pressure of 2 atm first we reach at point B which is condensation curce here vapour condenses and then it become liquid. At point C the freezing occured and it turns to solid.

zalm B dime 9+opcon 0.1 0.01 - attro -120 -60 o 60 18 -102 Solid

10. For being in solid state of the any compound at 100 K and 0.1 atm pressure the Critical temprature should be lesser than 100 K and critical pressure should be lesser than equal to 0.1 atm after these assumption we get a shaded region of sollid state.

So answers will be

(A) CO amd (b) CH4