Here are the example question, States at a temperature of 60�C and 1.20 atmospheres. Determine the physical state of the substance from the phase diagram shown above. All right, so we're dealing with 60�C, which we know is somewhere between 50�C here and 80.
Next they tell me the temp on the pressure, 1.20 atmospheres. Well, if we take a look here on our Y axis we have 760 tour. Remember 760 tour represents one atmosphere, but here we have a pressure of 1.20 which means our pressure is above this line here. So our pressure is higher than 760 Tor and the temperature is around 60.
So we can approximate this looks around 60 or so and it'll be somewhere above this line, so it'll fall within this sector of my face diagram. Now if we look that means it resides within the liquid phase. So here my answer would be option A. The unknown substance would be a liquid when the temperature is 60�C and 1.20 atmosphere based on the phase diagram shown before us.