DEPARTMENT OF CHEMICAL ENGINEERING, IIT MADRAS
CH1100 Fundamentals of Thermodynamics
Duration:50 mins QUIZ 1 Max marks:50
Answer allquestions
1) State TRUE OR FALSE OR FILL UP in YOUR ANSWER SHEET (5 x2 =10]
a) System refers to afixed quantity of matter with constant mass.
b) Water in an overhead tank at atmospheric pressure and 30°C and water
in a glass at atmosphericpressure and 30°C are at two different states.
c) Twosystems are in thermal equilibrium, if the properties of either system
do not change when they are brought in contact with each other through
wall.
d) Vaporizer in the nitric acid flowsheet operates under equilibrium.
e) In aquasi-equilibrium process, allstates including intermediate states are
equilibrium states.
2) The hydraulic lift in an auto-repair shop has a cylinder diameter of 0.2 m. To
what pressure should the hydraulic fluid be pumped to lift 40 kg of piston
and 700 kg of a car? Atmospheric pressure is 101 kPa. [10]
3) 1 kg of liquid water is taken in a cylinder fitted with a piston. The pressure is
maintained constant at 5 bar. The water is heated using a heater. Sometime
after the start of the experiment, the temperature measured is 100°C (state
A). After some more time of heating, it is observed that half the volume of
the cylinder is liquid and the rest is vapour (state B). The heating is continued
further until the entire cylinder is filled with vapour (state C). Measurements
indicate that the specific volume of vapour in state Cis 0.400 m³/kg. Indicate
the states A, Band Cin aPT diagram. Alsomark 5 bar on yaxis and, 100 °C
and saturation temperature for 5 bar on xaxis. [10]
4) Water at 120"C with a quality of 25% has its temperature raised 20"C in a
constant-volume process. What is the new quality and pressure? (Hint:
specific volume of mixture is same in state 1 and state 2) [10]
5) (a) What is the critical temperature (in °c) and critical pressure (in kPa) for
R134a? (b) R134a flows through apipe line of 10 cm diameter at a mass
flowrate of 0.1 kg/s. The pressure is 1400 kPa and temperature is 80°C. What
is the velocity in the pipe line? [10]
DEPARTMENT OF CHEMICAL ENGINEERING, IT MADRAS
CH1100Fundamentals of Thermodynamics
Duration:50 mins QUIZ II Max marks : 50
Answer all questions
Properties given in the question only should be used.
1) State TRUE OR FALSE OR FILL UP inYOUR ANSWERSHEET [5 x 2 = 10]
a) According to the thermodynamic definition of work, work is said to be
done by a system, during a given operation, if the sole effect external to
the system, could be reduced to the
b) Aprocess is carried out adiabatically following two paths Aand B. The
work interaction for the two paths is different. TRUE OR FALSE. !
c) The internal energy of vaporization for CO at -50 °C is 302 kJ/kg. The
enthalpy of vaporization forCO, at the same temperature is > 302 kJ/kg.
TRUE OR FALSE
d) Work done on or by acontrol volume where matter flows across the
boundary is called as ln d
e) The enthalpy of steam at the inlet of a throttling device is -1000 kJ/kg
(based on a newsteam table). Neglecting change in kinetic energy,
change in potential energy, heat and work transfer, the enthalpy at the
exit is
2) Acylinder containing 1kg of ammonia has an externally loaded piston.
Initially the ammonia is at 2 MPa and 180°C. It is now cooled to saturated
vapor at 40°C. Find the work (kJ) for the process, assuming a linear variation
of Pversus V.Take the properties of ammonia from the following tables. [12]
Superheated ammonia : P = 2000 kPa
Temperature (°C) V, m²/kg u, kJ/kg h, kJ/kg
100 0.08248 1466.1 1631.1
140 0.09447 1549.3 1738.2
180 0.10571 1630.6 1842.0
220 0.11652 1713.1 1946.1
Saturated ammonia
Temperature (°C) Pressure, kPa v, m²/kg Vig, m³/kg V, m°/kg
20 857.5 0.001638 0.14758 0.14922
40 1554.9 0.001725 0.08141 0.08313
60 2614.4 0.001834 0.04697 0.04880
1
3) A water-filled reactor with a volume of 1 m is at
20 MPa and 360"C and is placed inside a
Containment room, as shown in Figure. The room
is well insulated and initially evacuated. Due to a
failure, the reactor ruptures and the water fills the
containment room.
a) Find the minimum room volume (m) so that the final pressure does not
exceed 200 kPa.
b) What isthe mass fractionof water vapour in the room after the rupture?
Properties: Specific volume, internal energy and enthalpy of water (liquid) at
20 MPa and 360°C are 0.001823 m²/kg, 1702.8 kJ/kg and 1739.23 kJ/kg
respectively. At 200 kPa, the saturation temperature is 120.23°C, VE =
0.001061,Vig =0.88467, Va = 0.88573, uf = 504.47,Ufg = 2025.02, ug = 2529.49,
hf = 504.68, htg = 2201.96, ha = 2706.63.v in m²/kg, uand h in kJ/kg. (16]
4) A well-insulated diffuser, shown in Figure, has
air entering at 100 kPa and 300 K with a
velocity of 200 m/s. The inlet cross-sectional Ar
area of the diffuser is 100 mm².At the exit the
area is 860 mm', and the exit velocity is 20
m/s. Determine
a) the exit pressure (kPa) of the air
b) the exit temperature (K) of the air.
Assume potential energy changes are negligible.
Properties :The specific heat capacity of air is 1.004 kJ/kg K. Assume air to
behave as an ideal gas. [12]
Bet of Luck
