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Answerthe following question based on the P - T phase diagram of CO_2 as given in Q. 16 (a) CO_2 at 1 atm. Pressure and temperature-60^@C is compressed isothermally. Does it go through a liquid phase ? (b) What happens when CO_2 at 4 atm. pressure is cooled from room temperature at constatn pressure ? (c ) Describe qualitatively the changes in a given mass of solid CO^@ at 10 atm. pressure and temperature-65^@C as it is heated up to room temperature at constant pressure. (d) CO_2 is heated to a temperature 70^@C and compressed isothermally. What change in its properties do you expect to observe ? |
| Answer» Solution :(a) SINCE the temperature ` -60^@V` lies to the left of `56.6^@C` on the curve i.e. lies in the region of vapour and solid phase, so carbon dioxide will condens directily into solid without becoming liquid. (b) Since the pressure 4 ATM. Is less then 5.11 atm. the carbon dioxide will condense directly into solid without becoming liquid. (c ) When a solid `CO_2`at 10 atm. pressure and `-65^@C` temperature is heated it is first converted into a liquid. A further increases in temperature brings it into the vapour phase. At = P = 10 atm, if a horzontal line is drawn parallel to the T -axis , then the points of intersection of this line with the fusion and vaporization curve will give the fusion and BOILINGPOINTS of `CO_2` at 10 atm. (d) Since `70^@C` is higher then the critical temperature of `CO_2`, so the `CO_2` gas cannot be converted into liquid state on being compressed isothermally at `70^@C` it will remain in the vapour state. However, the gas will depart more and more form its perfect gas behaviour with the increase in pressure. | |