JNTU B.Tech II CHEMICAL PROCESS CALCULATIONS Previous Question Paper (November/December - 2018 - R13)

A solution of sodium chloride in water contains 230 grams of NaCl per liter at 20°C. The density of the solution at this temperature is 1.148 gm/cm³. Calculate the following: a) Composition in weight percent b) Volumetric percent of water c) Composition in mole percent d) Molality e) composition in atomic percent.

Write short notes on the following: a) Vapour pressure of immiscible liquids b) Critical properties estimation c) vapour pressure plots.

The vapor pressure of acetone at 273K is 8.52kpa and that at 352K is 194.9 kpa. Dry air initially at 101.3 kpa and 300K is allowed to get saturated with the vapors of acetone at constant temperature and volume. Determine: a) the total pressure of the mixture b) the mole percent of acetone in the final mixture.

In the operation of a synthetic ammonia plant a 1:3 nitrogen- hydrogen mixture is fed to the converter resulting in a 25% conversion to ammonia. The ammonia formed is separated by condensation, and the unconverted gases are recycled to the reactor. The initial nitrogen-hydrogen mixture contains 0.20 part of argon to 100 parts of N2-H2 mixture. The toleration limit of argon entering the reactor is assumed to be 5 parts to 100 parts of N2 and H2 by volume. Estimate the fraction of recycle that must be continually purged.

The spent acid from a nitrating process contains 33 % H2SO4, 36 % HNO3, and H2O by weight. This acid is to be strengthened by addition of concentrated sulfuric acid containing 95% H2SO4 and concentrated nitric acid containing 78% HNO3. The strengthened mixed acid is to contain 40 % H2SO4 and 43% HNO3. Calculate the quantities of spent and concentrated acids that should be mixed together to yield 1500 lb of the desired mixed acid.

Calculate the standard heat of formation of n-butane (g) (C4H10) at 298K from a knowledge of standard heat of combustion.

Data: ΔH°c (298K) of C (s) = -393.78 kJ/mol; H2(g) = -286.03 kJ/mol; C4H10 (g) = -2880.44 kJ/mol.

Calculate the standard enthalpy change of the following reaction at 298 K, H2S (g) + 1.5O2 (g) → H2O (g) + SO2 (g), from the knowledge of the standard heat of formation.

Data: ΔH°f (298K) of SO2 (g) = -297.263 kJ/mol; H2O(g) = -241.997 kJ/mol; H2S (g) = -20.097 kJ/mol.

Explain about calculation of calorific values for gases and liquids with examples.