Remember the expert uses the numbers in the problemrounded to the correct significant digits. The expert allows plusor minus 3% error in a calculation. So be careful when judging theexpert's response. You may be using the correct approach, but havea minor math, substitution, or rounding error.
1) A sample of water in the vapor phase (no liquid present) in aflask of constant volume exerts a pressure of 450 mm Hg at 98 C.The flask is slowly cooled.
a). Assuming no condensation, use the Ideal Gas Law to calculatethe pressure of the vapor at 87 C; at 72 C.
b) On the basis of your answers in a) and b), predict thepressure exerted by the water vapor in the flask at 87 C; at 72C.
2) Consider two closed containers each partially filled withliquid water one at 87 C and the other at 72 C. Can the pressure ofwater vapor in the gas phase in either container ever exceed theequilibrium vapor pressure at the particular temperature? What isthe vapor pressure for water at 87 C and at 72C?
3) Write a chemical equation describing the condensation processfor N2 and a chemical equation describing the freezingprocess for N2. For each process discuss the change inenthalpy and entropy that occurs. For each process describe theconditions (in terms of temperature) that support athermodynamically favorable change, and the conditions that do notsupport a thermodynamically favorable change.
4) The normal boiling point of methanol is 65.0 C and its Hvap =37.4 kJ mol-1. Calculate the temperature at which methanol has avapor pressure of 180.08 mmHg.
