Download GTU BE/B.Tech 2019 Winter 5th Sem New 2150503 Chemical Engineering Thermodynamics Ii Question Paper

FirstRanker.com

GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER- V (New) EXAMINATION - WINTER 2019

--- Content provided by‍ FirstRanker.com ---

Subject Code: 2150503 Date: 04/12/2019
Subject Name: Chemical Engineering Thermodynamics - IT
Time: 10:30 AM TO 01:00 PM Total Marks: 70

Instructions:
1. Attempt all questions.

--- Content provided by​ FirstRanker.com ---

2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Define: (1) Partial molar property (2) Activity coefficient (3) Fugacity. 03
(b) Discuss the excess Gibbs free energy relation with activity coefficient and chemical potential. 04
(c) Determine P-x-y data for chloroform (1) methanol (2) system at 35°C, vapor pressure of chloroform and methanol is 39.54 KPa and 27.95 KPa respectively. Margules parameters are: A₁₂=0.738 and A₂₁=1.868. 07

--- Content provided by⁠ FirstRanker.com ---

Q.2 (a) Define chemical potential and state its significance. 03
(b) Derive the expression to estimate fraction of initial mixture that is vaporized at equilibrium using flash vaporization calculation. 04
(c) Derive Margules equations for determination of activity coefficients of a binary system from the expression: 07
G^E/RT = (A₂₁x₁ + A₁₂x₂) x₁ x₂

OR

--- Content provided by‍ FirstRanker.com ---

(c) Show that for a binary system, Henry’s law is valid for component ‘1’ then Lewis Randall rule is valid for component ‘2’. 07

Q.3 (a) Write a short note on Bubble point equilibria. 03
(b) Write a short note on ‘fugacity of a pure liquid’. 04
(c) A gas mixture of SO_2(g), O₂ and inert A in mole ratio 1: 0.5: 2 enters in a reactor at 30bar and 900K to produce SO_3(g) as: 07
SO_2(g) + 0.5 O_2(g) -> SO_3(g). Determine the degree of conversion at equilibrium and composition of mixture leaving the reactor. Assume the reaction mixture behaves like an ideal gas. K =5.973 and K_y = 1.

--- Content provided by​ FirstRanker.com ---

OR

Q.3 (a) Derive summability relation for partial molar properties. 03
(b) Methanol (1)-acetone (2) system is described by the Van Laar activity coefficient model. At 60°C the model parameters are A₁₂ = 0.47 and A₂₁=0.78. Estimate the activity coefficients for a solution containing 15mole% of methanol. 04
(c) Derive equation for establish expression of standard Gibbs free energy change of chemical reaction as a function of thermodynamic equilibrium constant. 07

Q.4 (a) With neat diagram explain tangent-intercept method to estimate partial molar volume of a binary solution. 03

--- Content provided by‍ FirstRanker.com ---

(b) Discuss van Laar equations applicable in determination of activity co-efficient for VLE at low pressure with suitable examples. 04
(c) At T = 353K, vapor pressure of A, P_A^sat = 119.96KPa and that of B is P_B^sat =79.97KPa. Does an azeotrope exist at 353K? If so, determine the azeotropic pressure and composition. Given by ln ?₁=0.6x₂² and ln ?₂= 0.6x₁². 07

OR

Q.4 (a) Derive an expression for partial molar volumes V₁ and V₂ using following relationship for the molar volume of the binary liquid mixture of components 1 and 2. 03
V=x₁V₁+x₂V₂ +x₁ x₂[B+C(x₁ — x₂)]

--- Content provided by​ FirstRanker.com ---

(b) Explain any two methods for estimation of fugacity of pure gas. 04
(c) A gas mixture containing 30 mol% of CO, 50 mol% of H₂ and 20 mol% of inert gas is to be used for synthesis of methanol as: 07
CO_(g) +2H_{2 (g)} ->CH₃OH _(g)
Gases issued from the catalytic chambers are in chemical equilibrium with respect to the reaction at 30 bar and 625K. Assume that the equilibrium mixture forms an ideal solution, K = 5x10^-7 and K_f =1. What is the percentage conversion of CO?

Q.5 (a) Explain criteria of stability for a single phase binary system. 03

--- Content provided by‌ FirstRanker.com ---

(b) Draw neat diagram of idealized osmotic system and derive an equation for osmotic pressure difference. 04
(c) Mixtures of n-Heptane (A) and n-Octane (B) are expected to behave as an ideal solution .The total pressure over the system is 101.3 KPa. Use vapour pressure data given below and construct 07
a) T- x_A, y_A diagram b) Equilibrium diagram for A.

T,K	371.4	378	383	388	393	398.6
PAsat,KPa	101.3	125.3	140	160	180	205.3
PBsat KPa	44.4	55.6	64.5	74.8	86.6	101.3

OR

Q.5 (a) For VLE with suitable example; draw diagram for minimum azeotrope. 03

--- Content provided by​ FirstRanker.com ---

(b) Determine the number of degree of freedom F for each of following: 04
(1) A system prepared by partial decomposition of CaCO₃ into evacuated space.
(2) A system of two miscible non reacting species which exists as an azeotrope in VLE.
(c) With proper nomenclature draw three types of constant- pressure liquid-liquid solubility diagram. 07

FirstRanker.com

--- Content provided by FirstRanker.com ---