Question

1. on a hot summer day the temperature inside a room is 36 °c, barometer pressure is 763 mmHg and the relative humidity is 20%. A "cold-mist" vaporizer was installed to add moisture to the room. The room measure 5mx5mx4m. Calculate weight of water vaporized to completely saturate the room.

2. A stream of air at 40°C and 760 mmHg contains 20% water by volume.calculate:
a) The percentage of the vapour rhat condenses and the final composition of the gas phase if the air is cooled to 10°c at constant pressure.
b) The percentage of the vapour that condenses and the final composition of the gas phase if, instead of being cooled, the air is compressed isothermally to 1520 mmHg.
3. Air at 25°c with a dew point of 5°c enters a humidifier. The air leaving the unit has an absolute humidity of 0.01 kg of water per kilogram of dry air. the barometer reads 760 mmHg.
a) Calculate the kg of water that must be evaporated into the air for every 100 kg of dry air entering the unit.
b)if the air leaving the unit is saturated, what will be the temperature of this air?
4. it ia proposed to recover acetone, which is used as a solvent in an extraction process, by evaporation into a stream of nitrogen. The nitrogen entera the evaporator at a temperature at 30°c containing acetone such that is dew point is 10°c. it leaves at a temperature of 25°c with a dew point of 20°c. The barometric pressure is constant at 750 mmHg.
a) Calculate the moles of vapour evaporated per mole of vapour-free gas passing the evaporator
b) Calculate the weight of acetonr per 1000m^3 of gases entering the evaporator.
5. A mixture of dry air and NH3 enters an absorption tower at a rate of 100 ft^3/min at 27°c and 740 mmHg with 95% saturation. The vapour pressure of NH3 at 27°c is 50 mmHg. The gas leaves the tower at 730 mmHg and 20°c and contains 0.15% mol NH3. Calculate the kg NH3 in the liquid leaving the tower if the water enters the tower at 10 kg/min.

Answer 1