Section A
Q1. Answer all the parts of the question:
(a)
A solution of sodium chloride in water contains 220 g NaCl per litre at 20°C. The density of the solution at this temperature is 1.145 g/cm^3.
Calculate :
(i) Composition in weight percent
(ii) Volumetric percent of water
(iii) Composition in mole percent
(iv) Molality
(b) A steel casting of mass 10 kg at 1073.15 K is quenched in 100 kg of water at 303.15 K in an insulated container. The heat capacities of steel and water are 0.461 kJ/kg K and 4.23 kJ/kg K respectively. Calculate change in entropy of steel and water.
(c)
A gaseous feed of pure A (1 mol/L) enters in a mixed flow reactor having 2 L volume and reacts as follows :
2A → R, -rA = 0.05 CA2 mol/L.s.
Find what feed rate (L/min) will give an outlet concentration CA = 0.5 mol/L.
(d) A refrigerator kept in a room receives electrical energy of 130 W to drive the system, and it rejects 350 W to the room air. Find the COP of the refrigerator.
(e)
An aqueous feed of A and B (400 L/min, 100 mmol A/litre, 200 mmol B/litre) is to be converted to product in a plug flow reactor. The kinetics of the reaction are represented by
A + B → R, -rA = 200 CA.CB (mol)/(litre.min).
Find the volume of reactor needed for 99.9% conversion of A to product.
