Chemical Engineering Answers

Hydrochloric acid (A) diffuses through a thin film of water (B)

4 mm thick at 283 K and 1 atm ressure. The concentration of HCl at point 1 on

one boundary of the film is 12 wt % with density of 1060.7 kg/m3

and on the

other boundary, at point 2, is 4 wt % of density1020.15 kg/m3

. The diffusivity

of HCl in water at 293 K and 1.5 atm is 2.5 x 10-9 m

2

/s. Calculate the flux of

HCl considering water to be stagnant.

Ammonia is being absorbed from air-ammonia mixture by

sulphuric acid solution. The concentration of ammonia 2.5 cm from the acid

surface is 40% by volume and concentration at the acid surface is zero. The

total pressure of the system is 400 mm Hg and the temperature is 288 K. The

value of diffusivity is 1.73 X 10-5 m2

/s at 293 K and 1 atm. Calculate the

following:

(i) Rate of absorption of ammonia across 0.045 m2

of acid surface.

(ii) Concentration of ammonia 1.25 cm from the acid surface

To condition the air in an office building in the winter, 1000 cm3 of moist air at 101 kPa and22oC enters the process. The air leaves the process at 98 kPa. How many kg of water

vapour are added to each kg of wet air entering the process? Partial pressure of water in

entering air is 1.31 kPa; Partial pressure of water in leaving air is 18.14 kPa.

In steady state ideal PFR, the concentration of reactant_____decreases/increases/stays constant) from entrance to exit of the reacto reactor?

5)In steady state ideal CSTR, the exit concentratar of reactant( is equal to,is less than,is grater than) the concentration of the reactant inside the reactor?

4)During the progress of the reaction in the batch reactor, the concentration of reactant(decreases,increases)with increasing time?

3)Write the expression for rate of reaction of reactant A if it decomposes according to elementary reaction, 2A->P+R

2)Is the rate constant depends on the concentration of reactant?(yes/no)

1) Is the experimentally determined rate equition depends on the type of reactor used for experiments? (Yes / No)

Which of the following is the best reactor/reactors set up for autocatalytic reactions? ( )

A) PFF followed by MFR

8) MFR followed by PFR

C) Single MFR DY Single PFR