Chemical Engineering Answers

Define hardness. Explain why hard water does not give lather with soap

A 1300-kg car is to accelerate from rest to a speed of 30.0 m/s in a time of 12.0s as it climbs a 15.0 hill Assuming uniform acceleration, what minimum horsepower is needed to accelerate the car in this way?

A system is taken from state 1 to state 2 along a path A. During this

process it received 200 kJ energy as heat and does 100 kJ work. If the

system is taken from state 2 to state 1 by a different path B, it is necessary

to spend 150 kJ work on the system. Determine the heat interaction along

the path B. Suppose the system is restored to state 1 from state 2 by an

adiabatic path C, how much work has to the done on the system?

The acceleration of gravity is a function of elevation above sea level by

𝑔 = 980.6 − 3.086 × 10−6𝐻

where g is in cm/s2, and H is in cm. If an aeroplane weights 90 kN at sea

level, what is the gravity force upon it at 10,000 m elevation? What is the

percentage difference from the sea-level weight?

The falling rate portion of the drying time for a particle of skim milk begins at the critical moisture content of 25%, and the final moisture content is 4%. The air used for drying is 120°C and was heated from ambient air of 20°C and 40% RH. The particle size at the critical moisture content is 20 microns, and the specific heat of the product solids is 2.0 kJ/kg K. The mass diffusivity for water within the product particle is 3.7 x 10-12 m2/s, and the density of the product particle is 1150 kg/m3. If the equilibrium moisture content for the product is 3.5%, estimate the time for the falling rate portion of drying. 

b. If 5000 m3/min of heated air is needed for product drying, determine the thermal energy needed to heat the air to 120°C. 

1. Liquid reactant A decomposes as follows:

A feed of aqueous A (𝐶𝐴𝑜= 40 mol/m3) enters a reactor, decomposes, and

a mixture of A, R, and S leaves.

I. Find 𝐶𝑅and 𝐶𝑆

for 𝑋, = 0.9 and t=2min in a Batch Reactor?

II. Find 𝐶𝑅and 𝐶𝑆

for 𝑋, = 0.9 and 𝛳𝐹 = 2.5 𝑚𝑖𝑛 in a Tank- Reactors?

III. Find 𝐶𝑅and 𝐶𝑆

for 𝑋, = 0.9 and 𝛳𝐹 = 2.5 𝑚𝑖𝑛 in a plug flow reactor?

IV. Find selectivity and yield for Batch Reactor, Tank- Reactors and plug flow

reactor?

Note:- Before find 𝐶𝑅and 𝐶𝑆

first proof 𝐶𝑅and 𝐶𝑆 By substituting the value of 𝑛𝐴𝑎𝑛𝑑 𝐹𝐴 and

then integrating assume the re

Carbon disulphide (CS2) is used to extract iodine from its aqueous solution. The distribution of iodine between Carbon disulphide (CS2) and Water at equilibrium is given by, Y=550.X. Calculate the concentration of iodine in aqueous phase of 1 liter of water is stirred with 50 ml of Carbon disulphide (CS2) for two stage extraction operation.

Carbon disulphide (CS2) is used to extract iodine from its aqueous solution. The distribution of iodine between Carbon disulphide (CS2) and Water at equilibrium is given by, Y=550.X. Calculate the concentration of iodine in aqueous phase of 1 liter of water is stirred with 50 ml of Carbon disulphide (CS2) for two stage extraction operation.

4.32 (a) Nitrogen gas (C P =30 kJ/ kmol K) at 1 bar and 300 K is to be compressed to 10 bar and

450 K at a rate of 5000 kg/h. Cooling water (C_{P} = 4.1868kJ / k * gK) enters the compressor at 300 K at the rate of 7500 kg/h and leaves at 320 K. Determine the power required by the compressor. (b) For the same conditions of nitrogen as in the previous part, determine the minimum power required by the compressor. The rate of circulation and the inlet temperature of cooling water

remain the same as above.

In slurry reactor pure reactant gas is bubbled through liquid containing suspended catalyst particles. Initially the reactant gas which enters the liquid must diffuse through the liquid film surrounding the catalyst particle. At the surface of particle reactant yields product according to first order kinetics .Draw the concentration profile of gaseous reactant in slurry reactor and derive an expression for the rate of reaction in terms of resistances encountered in the reactor.