Bissoy.com
Doctors Medicines MCQs Q&A

A piston-cylinder has the piston loaded with outside atmospheric pressure and piston mass to a pressure of 150 kPa. It contains water at −2°C, which is heated until the water becomes saturated vapour. Find the specific work for the process.

A piston-cylinder has the piston loaded with outside atmospheric pressure and piston mass to a pressure of 150 kPa. It contains water at −2°C, which is heated until the water becomes saturated vapour. Find the specific work for the process. Correct Answer 173.7 kJ/kg

Energy Eq. per unit mass: u2 – u1 = 1q2 – 1w2 Process: P = constant = P1, => work = P1(v2 – v1) State 1: T1 , P1 => saturated solid; v1 = 1.09×10^(-3) m3/kg, u1 = -337.62 kJ/kg State 2: x = 1, P2 = P1 = 150 kPa; v2 = vg(P2) = 1.1593 m3/kg, T2 = 111.4°C ; u2 = 2519.7 kJ/kg work = P1(v2 -v1) = 150 = 173.7 kJ/kg.

Related Questions

A piston-cylinder contains 0.1 kg saturated liquid and vapour water at 100 kPa with quality 25%. The mass of the piston is such that a pressure of 500 kPa will float it. The water is heated to 300°C. Find the work.
10kg of water in a piston-cylinder exists as saturated liquid/vapour at 100 kPa, with a quality of 50%. It is now heated till the volume triples. The mass of piston is such that a cylinder pressure of 200 kPa will float it. Find the heat transfer in the process.
Consider the following statements: 1. There is no change in temperature when a liquid is being evaporated into vapour 2. Vapour is a mixed phase of liquid and gas in the zone between saturated liquid line and saturated vapour line 3. The saturated dry vapour curve is steeper as compared to saturated liquid curve on a T-s diagram 4. The enthalpy of vaporization decreases with increase in pressure Which of the above statements are correct?
A piston-cylinder device initially contains air at 150 kPa and 27°C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine work done by the air.
A vessel of volume 1000 m3 contains air which is saturated with water vapour. The total pressure and temperature are 100 kPa and 20°C respectively. Assuming that the vapour pressure of water at 20°C is 2.34 kPa, the amount of water vapour (in kg) in the vessel is approximately
A piston-cylinder device initially contains air at 150 kPa and 27°C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine the final temperature.
A piston-cylinder device initially contains air at 150 kPa and 27°C. At this state, the volume is 400 litre. The mass of the piston is such that a 350 kPa pressure is required to move it. The air is now heated until its volume has doubled. Determine the total heat transferred to the air.
An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively.The humidity of air sample expressed as kg of water vapour/kg of dry air is
For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3. Fugacity of water (in kPa) at 9000 kPa will be
10 kg of water in a piston-cylinder exists as saturated liquid/vapour at 100 kPa, with a quality of 50%. It is now heated till the volume triples. The mass of the piston is such that a cylinder pressure of 200kPa will float it. Find the work given out by the water.