Physical Chemistry Answers

The e.m.f. of the following cell reaction is 0.6753 V at 25 ℃ and 0.6915 V at 0 ℃. Cd(s) | CdCl2.5H2O(saturated) || AgCl(s) | Ag(s)

(i) Give the balance for the cell reaction

(ii) Calculate the free energy G, enthalpy H and entropy S, change of the cell reaction at 25 ℃.

The solubility of silver chloride is 1.37*10^-5 M at 298K. Calculate it's solubility product

1The solubility of silver chloride is 1.37*

1. Under nitrous oxide, NO, anesthesia, a small amount of NO diffuses into the middle ear through mucosal blood vessels and across the tympanic membrane, causing increase in gas pressure in the middle ear. Assume that an eardrum has an area of 0 mm² and will normally vent excess pressure by opening the Eustachian tube when the collisional rate is greater than 9.0 x 10¹¹ collision/s. Determine the minimum total pressure (in N/m²) of NO in the inner ear at body temperature (37.0°C) to initiate venting. Assume that venting has occurred several times so that the gas in the inner ear is pure NO. 1 Newton = 1kg ms2

4gm of a divalent metal reacts with chlorine to produce 11.1gm of its metal chloride. Calculate equivalent weight of the metal.

1.   (a)    The following Table 1 shows kinetic study values obtained from second order the gas phase reaction.

                                        X₂ + H₂   → 2HX

Table 1

T (K) k (cm³ mol^-1 s^-1)

600 4.6 x 10²

700 9.7 x 10³

800 1.3 x 10⁵

1000 3.1 x 10⁶ 

[Average molar mass of reactant is 128 g mol^-1]                  

Find:

(i)           The collision frequency at 700 K (in m³ s^-1).

(ii)          The collisions diameter.         

[20 Marks]

Some calculations related to oxygen enrichment of blast are given in the Table below. Given: heat capacity of solid (kcal/THMoC) for upper and lower part of BF are 500 and 1700, respectively. Average volumetric heat capacities (kcal/Nm3 - oC) of air and blast furnace gas are 0.333, and 0.337, respectively. Blast preheat at 1000oC and burden inlet at 30oC. Assume, tuyer gas is 100% CO, and heat of reaction for CO formation is 111000kJ/kg-mole. Carbon rate 400 kg/THM. Fill in the blanks of the table below. % O2 in air Tuyer gas volume Nm3 /kg.C Tuyer gas heat content kcal/kgC RAFT ( oC) heat capacity of gas kcal/THMoC Top gas temperature ( oC) Blast Volume Nm3 /kg.C 21 4.44 5.38 3682 2032 725 300 27 (14)________ 4.39 (15)_________ 2267 592 (16)________ 29 3.22 4.15 3274 2340 (17) _______ 123 36 2.59 (18)_______ 3066 (19)________ 485 (20)________

a.Blast Volume (Nm3 /kg.C) at 27% oxygen in air is ______________.

b.Tuyer gas heat content in kcal/kg.C at 27% oxygen in air is _____________

c.Top gas temperature ( oC) for 25% oxygen in air is ______________.

d.Heat capacity of gas in kcal/THMoC at 29% oxygen in air is ______________.

e.Tuyer gas volume in Nm3 /kg.C at 36% oxygen in air is______________.

f.RAFT in oC at 36% oxygen in air is ______________.

g.Top gas temperature ( oC) for 36% oxygen enrichment in air is ______________

Following data are given for a blast furnace with and without oil injection. Items Without oil injection With oil injection Coke rate (kg/THM) 660 482 Oil Injection (kg/THM) 0 155 Blast temperature (oC) 1020 920 Blast quantity (Nm3 /THM) 1802 1297 Top gas temperature (oC) 235 235 Production (THM/hr.) 1.248 1.642 Calculate the replacement ratio.

In order to increase productivity, 40% more blast is injected in BF per unit time (base case at 2400 Nm3 /m2 /hr, average pressure at 1.8 atm and pressure drop of 1.4 atm). To restrict channelling, it is intended to maintain the pressure drop and hence linear velocity of gas through BF to be constant by enhancing top pressure. What will be the bottom pressure to achieve this? Assume, velocity exponent for pressure drop is at 1.75. 

A furnace is operating with top and bottom pressures as 1.1 and 2.5 atm, respectively. If we intend to blow 30% more blast to enhance coke burning rate and productivity, keeping pressure drop and linear velocity constant under HTP. Calculate the required top pressure. Take velocity exponent for pressure drop is at 1.75. 

In dry zone of a Blast Furnace (BF), following data are given: BF gas temperature = 1000oC, gas flow rate=4000 Nm3 /m2 /hr, gas density at NTP =1.5×10-3 g/cc, viscosity at 1000oC = 480×10-6 g/cm-s, particle diameter = 4 cm, average pressure = 1.6 atm. 

a.Calculate the pressure drop (mm of H2O/cm) for gas voidage 0.25. 

b.Calculate the percentage decrease in pressure drop when the gas voidage is increased from 0.25 to 0.35.

c.Calculate the percentage increase in pressure drop when the gas voidage is decreased to 0.20 from 0.25.