1
Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEMESTER-IV EXAMINATION WINTER 2017
Subject Code: 2140406 Date:17/11/2017
Subject Name: Stoichiometry
Time: 02:30 PM TO 05:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Atomic Wt: Na 23, 16, Mg=24, Ca=40, Cl=35.5
Q.1

Define selectivity, yield and conversion.
03

Make following conversions:
2.1gm/cm3 to lb/ft3 550 kPa to Torr
04

The gaseous reaction A → 2B C takes place isothermally in a constant pressure reactor. Starting with a mixture of 75% A and 25% inerts (by volume), in a specified time the volume doubles. Calculate the conversion achieved.
07
Q.2

Define Relative humidity, Standard Heat of formation, Humid volume.
03

Find out the value of the universal gas constant R in following units:
atm.lit/mol.K
ii) J/mol.K
iii) KPa.m3/kmol.K
04

Explain bypass and purge streams with suitable diagram.
07
OR

An aqueous solution of acetic acid of 35% by weight has a density 1.04 kg/lit at 298 K. Find the molarity, normality and molality of the solution.
07
Q.3

Explain Dalton's law ii) Raoult's law iii) Henry's law.
03

In the Caustic soda plant, in multiple effect evaporators, the second effect is maintained under vacuum of 410 torr. Find the absolute pressure in kgf/cm2, kPa, atm, N/m2.
04

Carbon dioxide is dissolved to the extent of 38 liters per liter of solution of 27.5% (by weight) DAPOL (diamino-iso-propanol [C3H4OH(NH2)2]. The volume of carbon dioxide gas measured at 101.325 kPa and 288.6 K. Find the weight and mole% of carbon dioxide in the solution. If the density of DAPOL solution as 1.04 kg/l.
07
OR
Q.3

Iron metal weighs 200 lb occupies a volume of 117 L. Find the density in kg/m3
03

Explain material balance for distillation and crystallization operations.
04

Pure methane is heated from 303 K to 523 K at atmospheric pressure. Calculate the heat added per kmole methane using Cp data.
Cp a bT cT2 dT3 . Data for methane: a 19.2494, b × 103 52.1135, c × 106 11.973, d × 109 -11.3173.
07
2
Q.4

Explain recycle operation with suitable diagram.
03

A weight of 1.10 kg of Carbon dioxide occupies a volume of 33 liter at 300 K. Using the Vander Waals equation of state, calculate the pressure.Data: For CO2 take a 3.60 and b 4.3 x 10-2 m3/kmol
04

An evaporator system concentrating weak liquor from to 50% solids handles 100 kg of solids per hour. If the same system is to concentrate a weak liquor from to find the capacity of the system in terms of solids that can be handled per hour assuming water evaporation capacity to be same in both cases.
07
OR
Q.4

Differentiate between
Endothermic and exothermic reactions
ii) Sensible heat and latent heat
03

A sample of aqueous triethanolamine solution contains 47% TEA (on volume basis). If density of pure TEA is 1125 kg/m3, find the weight of TEA in the solution
04

It is required to make 1000 kg mixed acid containing 60% H2SO4, 32% HNO3 and 8%water by blending spent acid containing 11.3% HNO3, 44.4% H2SO2 and 44.3% H2O, aqueous 90% HNO3 and aqueous 98% H2SO4. All percentage are by weight. Calculate the quantities of each of the three acids required for blending.
07
Q.5

Using Antoine equation calculate the vapour pressure of acetic acid at 316 K. Data: A=6.5127 1533.30 -50.8500
03

A heat exchanger for cooling a hot hydrocarbon liquid uses 10000 kg/hr of cooling water, which enters the exchanger at 294 K. The hot oil at the rate of 5000 kg/hr enters at 423 K and leaves at 338 K and has an average heat capacity of 2.51 KJ/(kg.K). Calculate the outlet temperature of water.
04

Single effect evaporator concentrating weak liquor containing solids to 55% solids (by weight) is fed with 5000 kg/h of weak liquor. Calculate: water evaporated per hour, and flow rate of thick liquor.
07
OR
Q.5

Define standard heat of combustion, standard heat of reaction and dew point.
03

Formaldehyde is produced from methanol catalytic reactor. The production rate of formaldehyde is 1000 kg/h. If conversion of methanol is calculate the required feed rate of methanol.
04

A gas mixture has the following composition by volume: C2H2: 32.0%, C6H6: 21.0%, Oxygen: CH4 16.0%, C2H6 Nitrogen: 9.0 Find: the average molar mass of the gas mixture, the composition by mass and the density of gas mixture in kg/m3 at 101.325 KPa and 300 K.
07