For a mixture of methanol (1) and methyl acetate (2): a.) Assume the mixture is found to obey Raoult’s law. At 60ºC and x1 = 0.25, what is the system pressure and the composition in the vapor? b.) Assume the mixture is found to obey Raoult’s law. At 60ºC and 90 kPa, what are the compositions in each phase? c.) Assume the mixture is NOT an ideal solution, and instead follows Modified Raoult’s law. It has been found experimentally that: ln(%) = 1.25x- - and ln(-) = 1.25x% -. At 100ºC and x1 = 0.75, what is the system pressure and the composition in the vapor?

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?