Question 61. An insulated, evacuated container is connected to a supply line of an ideal gas at pressure Ps, temperature Ts and specific volume Vs. The container is filled with the gas until the pressure in the container reaches Ps. There is no heat transfer between the supply line to the container, and kinetic and potential energies are negligible. If CP and CV are the heat capacities at constant pressure and constant volume, respectively (Ï’ = CP/CV), then the final temperature of the gas in the container is

Question 62. A bed of spherical glass beads (density 3000 kg/m3 diameter 1 mm, bed porosity 0.5) is to be fluidized by a liquid of density 1000 kg/m3 and viscosity 0.1 Pa.s. Assume that the Reynolds number based on particle diameter is very small compared to one. If g = 10 m/s2 then the minimum velocity (in m/s) required to fluidize the bed is

Question 63. The rate-controlling step for the solid-catalyzed irreversible reaction A + B ---> C is known to be the reaction of adsorbed A with adsorbed B to give adsorbed C . If Pi is the partial pressure of component i and Ki is the adsorption equilibrium constant of component i , then the form of the Langmuir-Hinshelwood rate expression will be

Question 64. In a counter-flow double pipe heat exchanger, oil (m = 2 kg/s, CP = 2.1 kJ/kg.°C) is cooled from 90 °C to 40 °C by water (m = 1 kg/s, CP 4.2 kJ/kg.°C) which enters the inner tube at 10 °C. The radius of the inner tube is 3 cm and its length is 5 m. Neglecting the wall resistance, the overall heat
transfer coefficient based on the inner radius, in kW / m2. K, is

Question 65. Heat is generated at a steady rate of 100 W due to resistance heating in a long wire (length = 5 m, diameter = 2 mm). This wire is wrapped with an insulation of thickness 1 mm that has a thermal conductivity of 0.1 W/m.K. The insulated wire is exposed to air at 30°C. The convective heat transfer between the wire and surrounding air is characterized by a heat transfer coefficient of 10 W/m2.K. The temperature (in °C) at the interface between the wire and the insulation is

Question 66. A crosscurrent cascade of N ideal stages is used to treat a feed stream of molar flow rate E. The feed stream contains a solute which is to be recovered by a pure solvent having a molar flow rate S. The solvent is divided equally between these N stages. The linear equilibrium curve relating the mole fractions x and y* of the solute in the raffinate and the extract respectively, is given by y* = m x. Assume dilute conditions. The ratio of the solute mole fraction in the original feed to
that in the exit raffinate stream i.e. (x0/xN) is given by

Question 67. The vapor-liquid equilibrium curve of a binary mixture A-B, may be approximated by a linear equation over a narrow range of liquid mole fractions ( 0.2 < xA < 0.3) as follows  y*A = 1.325 xA + 0.121 Here y*A is the mole fraction of A in the vapor. 100 moles of a feed (xA, F = 0.28) is batch distilled to a final residue (xA, W = 0.2). Using the Rayleigh equation, the number of moles of the residue left behind in the distillation unit, up to 2 digits after the decimal point, is ____________

Question 68. A study was conducted in which water was pumped through cylindrical pipes made of a sparingly soluble solid. For a given pipe and certain flow conditions, the mass transfer coefficient kc has been calculated as 1 mm/s using the correlation Sh = 0.025 Re0.6 Sc0.33 If the velocity of the fluid and the diameter of the pipe are both doubled, what is the new value of kc in mm/s, up to 2 digits after the decimal point? ____________

Question 69. A first order liquid phase reaction is carried out isothermally at a steady state in a CSTR and 90% conversion is attained. With the same inlet conditions and for the same overall conversion, if the CSTR is replaced by two smaller and identical isothermal CSTRs in series, the % reduction in total volume, to the nearest integer, is ____________

Question 70. A unit gain 2nd order underdamped process has a period of oscillation 1 second and decay ratio 0.25. The transfer function of the process is