Final exam questions for Chemical Engineer BSc

Physical Chemistry(TKBE0401_EN, TKBE0403_EN, TKBL0403_EN)

1.1 The properties of gases: perfect gas, non-ideal gases. The perfect gas equations. The ideal gas law. Non-ideal gases: the compression factor, the virial equation, the van der Waals equation and its parameters, critical point. Fundamentals of the kinetic theory of gases. The molecular origin of pressure. The Maxwell distribution of speeds for gases.

2.The zeroth and the first law of thermodynamics. The zeroth law of thermodynamics: temperature, thermal equilibrium.The first law of thermodynamics. Internal energy, work, heat, heat capacity, enthalpy. Thermodynamic characterisation of ideal and non-ideal gases: the Jouleand the Joule-Thomson experiments. Condensation of gases, practical issues.

3.Thermochemistry: application of the first law of thermodynamics to reactive systems. Thermochemical equations.Standard state. Enthalpy of formation, combustion and reaction. Hess’s law of constant heat summation. Kirchhoff’s law for temperature variation of the standard enthalpy of reaction.

4.The second law of thermodynamics: Various formulations of the second law. Reversible and irreversible processes. Entropy theorem. Thermodynamic and statistical definition of entropy. Standard entropy of reaction. Thermodynamics and practical issues of heat engines, and refrigerators.

5.The third law of thermodynamics: The thermodynamic temperature. Absolute zero of temperature and its unattainability. The third law of thermodynamics. The variation of entropy with temperature. The absolute and standard values of the entropy. Standard entropy of reaction.

6.Free energy functions:The Clausius inequality. Defining criteria for spontaneity by combining the first and second laws of thermodynamics. Definition of Helmholtz and Gibbs free energy functions. Free energy and spontaneity. Application of the Gibbs free energy: standard free energy of formation, standard free energy of reaction.

7.Physical transformation of pure substances:The stabilities of phases. The thernodynamic criterion of equilibrium. Phase transitions and the location of phase boundaries.The Clapeyron- and Clausius–Clapeyron-equations. Typical phase diagrams: carbon-dioxide and water.

8.Thermodynamics of simple mixtures:Partial molar volume, chemical potential, the Gibbs-Duhem equation. The thermodynamics of ideal mixtures. The chemical potential of liquids. Raoult’s- and Henry’s laws of dilute solutions. The chemical activity of solvent and solute, standard state.

9.Thermodynamics of solutions: Thermodynamics of dilute solutions. Colligative properties. Depression of freezing point, elevation of boiling point, osmosis: thermodynamics and practical issues.

10.Mixtures of volatile liquids:vapour pressure-composition and boiling temperature-composition diagrams for ideal and non-ideal two-component systems.The lever rule. The distillation of mixtures. Azeotropes. Vacuum and steam distillations. Partition equilibrium, partition constant, extraction.

11. Thermodynamics of multiphase and multicomponent system:Component, phases, degrees of freedoms. Thephase rule (Gibbs-law) and its application to pure substances and two component systems. Liquid-liquid phase diagrams. Liquid-solid phase diagrams. Eutectics.

12.Chemical equilibrium: The reaction Gibbs energy and its application to characterizing chemical equilibrium. Exergonic and endergonic reactions. The thermodynamicequilibrium constant and its relation to the standard reaction Gibbs energy. Definition of Kp, Kx and Kc, their relationships. Determining equilibrium constant from thermochemical data.

13. The response of equilibriatoconditions:Le Chatalier’sprinciple. The response of equilibria to pressure, temperature and composition. The temperature dependence of the equilibrium constant: The van’t Hoff equation. Practical applications.

14.The response of equilibrium to pH:The Brönsted-theory.Acid–base equilibria in water. Dissociation and protonation constants. The autoprotolysis of water. The pH scale. Acid-base titrations.The Henderson–Hasselbalch equation. Practical applications: buffers and acid-base indicators.

15.Thermodynamic properties of ions in solution:Standard functions of formation of ions. Activity of ions in solution. Mean activity coefficients. The Debey–Hückel limiting law. Ionic strength of solutions. Solubility equilibria and solubility constant of salts.

16. Equilibrium electrochemistry: Electrochemical cells. Half-reactions and electrodes. Varieties of electrodes: gas, metal/metal ion,metal/insoluble salt and redox. TheNernst equation of an electrode. Standard electrode potentials and the standard hydrogen electrode.The operational principle of the glass electrode.

17.Thermodynamics of electrochemical cells. Daniell cell as an example. Varietiesof electrochemical cells. Electromotive force, the Nernst equation of the cell. The cell potential and its relation to the reaction Gibbs free energy. The standard cell potential. Other thermodynamic functions of the cell reaction.

18. Practical electrochemistry.Faraday’s laws of electrolysis.Industrial applications. Selective examples of primary and secondary cells: batteries and accumulators, respectively.Electrochemistry of corrosion.

19. Transport processes: diffusion, thermal conductivity, viscosity.Notion and thermodynamic view of diffusion. The diffusional flux.Fick’sfirst and second laws of diffusion. The Einstein-relation, the Nernst-Einsteinand the Stokes-Einstein equations. Notion of heat conduction, its flux and the thermal conductivity coefficient.Viscosity and its molecular explanation. Measurement of viscosity.

20. Conductivity of electrolytes, ionic motion. Conductance and conductivity of electrolyte solutions.Measurement of conductivity. Molar conductivity and its dependence on concentration: weak and strong electrolytes. The Kohlrausch lawof the independent migration of ions. Ionic motion in electric field: mobility and molar conductivity. Electrolysis: definition and measurement of transport number. Its relation to ionic mobility.

21. The rate of chemical reactions. The definition of rate, rate laws, reaction order and rate constant.The determination of the rate laws: isolation method, pseudofirst-order rate laws,method of initial rates. Integrated rate laws of first and second order reactions. Reaction half lives and time constants.

22. Accounting for the rate laws. Elementary reactions, molecularity, rate laws of elementary reactions.Consecutive and competitive elementary reactions.Kinetic approach to chemical equilibrium. Relaxation methods.

23. Mechanism of complex reactions. Reaction mechanisms. The rate-determining step. Simplifying mechanism of complex reactions:the steady-state approximation, pre-equilibrium.Unimolecular reactions: the Lindemann-Hinshelwood mechanism.

24. Enzyme reactions.The Michaelis–Menten mechanism of enzyme catalysis. The Michaelis constant and its determination.The maximum rate of the enzyme catalysis, the catalytic efficiency of enzymes: the turnover frequency.

25. Chain reactions. Typical steps of a chain reaction: initiation, propagation, retardation, branching and termination. The rate laws and mechanism of typical chain reactions: pyrolysis and the hydrogen-bromine reaction. Chain polimerization. Thermal explosion and chain-branching explosion. The explosion limits of hydrogen-oxygen reaction.

26. Photochemistry, catalysis, autocatalysis. Principles of photochemistry. The primary quantum yield. Kinetics of photophysical and photochemical processes. Quenching. Features of homogeneous catalysis, acid and base catalysis. Characterization of autocatalytic reactions.Oscillating reactions:the Belousov-Zhabotinskii reaction.

27. The temperature dependence of reaction rates.The Arrhenius-equation and interpretation of its parameters.Collision theory: collision rates in gases, the activation energy, the steric requirement.The activated complex theory.The Eyring-equation and its application to calculate Gibbs energy, enthalpy and entropy of activation.

28. Reactions in solutions:Mechanism of reactions in solutions: the cage effect and the formation of the encounter pair. Two limiting cases: activation-controlled and diffusion-controlled reactions.Rate constant of diffusion-controlled reactions, the Einstein-Stokes equation.

29. Processes at solid surfaces.Physisorption and chemisorption.The extent of adsorption. The Langmuir isotherm. The BET isotherm. The rate of desorption.

30. Reactions at solid surfaces. Adsorption and catalysis. The Eley–Ridealandthe Langmuir–Hinshelwood-mechanism. Examples of catalysis: hydrogenation, oxidation, cracking and reforming.

Questions of Unit Operations

  1. Introduction to chemical engineering. Chemical technology and unit operations. Physical quantities, measurement. Units and dimensions. Basic units and derived unites. SI system of units, CGS system of units and FPS system of units. (MSH pp. 3-12 and GE pp. 5-9).
  2. Dimensionless equations and consistent units. Dimensional equations. Dimensional analysis. (MSH pp. 14-19)
  3. Extensive- and intensive quantities. Four extensive quantities of the chemical engineering. Stream and flux density of extensive quantities. Mechanism of transport processes. Convective transport, bulk flow. (GU pp. 1-3).
  4. Conductive transport. General molecular transport equation and general property balance. Three fundamental laws of transport phenomena. Mass balance in a flowing fluid; Continuity. (GU pp. 3-9).
  5. General Property Balance. Sources and local changes. Damköhler equation. Transfer stream. Benedek-László equations. Shell balance equation. (GU pp. 9-16).
  6. Fluid statics and its applications. Nature of fluids. Classification of the fluids. Pressure, absolute and gauge pressure. Unites of pressure. Pressure distribution for a fluid at rest. Incompressible fluid. Head of a liquid. Buoyancy and floating body. Measurement of pressure, simple U tube manometer, inclined manometer, two-fluid U tube, Bourdon pressure gage. Gravity separator for two immiscible liquids. Compressible fluid, barometric equation. (MSH pp. 31-36 and GE pp. 34-42).
  7. Fluid flow phenomena. Fluid in motion. Types of fluid flow, Reynolds’ experiments and Reynolds number. Velocity gradient and rate of shear. Rheological properties of fluids. Time-dependent flow. Viscosity of Newtonian fluids. Units of viscosity. (MSH pp. 45-50 and GE pp. 47-53)
  8. Basic equations of fluid flow. Mass balance in a flowing fluid: continuity. One-dimensional flow, mass flow through the differential area, average velocity. Shell balance for mass flow. Macroscopic mechanical energy balance of flowing fluids. Bernoulli’s equation without friction. Correction of Bernoulli equation for fluid friction. (MSH pp.68-72,81-82,86-93)
  9. Incompressible flow in a pipes and channels. Shear-stress and skin friction in a pipe. Determination of friction factor by dimensional analysis (from lecture). Effect of roughness on friction factor, Friction from changes in velocity or direction (MSH pp.98-104,113-116,121-125)
  10. Flow around immersed objects, motion of particles in fluid. Drag force and drag coefficients. Sedimentation. Terminal velocity. Drag coefficient as a function of the Reynolds number. Drag coefficients of typical shapes. (MSH pp.155-159)
  11. Mixing of liquid as a problem of the flow around immersed object. Differential equation of force for impellers. Power consumption of stirrer.(MSH pp.244-)
  12. Definition of heat and temperature. Units of heat and temperature. Definition of specific heat and heat capacity and latent heat. Heat flow rate and heat flux. Nature of heat flow. Mechanism of heat stream. (MSH pp 293-297),
  13. Convection heat flow: Heat stream by bulk flow.
  14. Conduction heat transfer. Fourier’s law of heat conduction. Thermal conductivity. Steady-state conduction. Heat conduction in a flat wall. Heat conduction through the plane walls in series. Conduction through material in parallel. Heat conduction through a hollow cylinder. (MSH pp.299-308). Heat conduction through multilayer cylinder. (GE pp.246-248).
  15. Surface heat transfer. Newton’s law of cooling. Heat transfer coefficient.
  16. Heat transition. Combined surface heat transfer and heat conduction. Overall heat transfer coefficient.
  17. Principles of heat flow in fluids. Typical heat-exchange equipment. “Double-pipe” and “shell and tube” heat exchanger. Heat balances in heat exchanger. (MSH pp.325-332). Logarithmic mean temperature difference (GE pp.267-268).
  18. Determination of heat transfer coefficient with dimensional analysis. Empirical equations. Tube-side coefficient: Sieder-Tate equation (MSH pp.358-359), Shell-side coefficient: Donohue equation(MSH pp.449-450) Colburn analogy: Colburn j factor (MSH p.368)
  19. Radiation heat transfer. Fundamental facts concerning radiation. Emission of radiation. Absorption of radiation by opaque solids. Kirchhoff’s law. Radiation between surfaces (MSH pp.417-426).
  20. Principles of diffusion and mass transfer between phases. Theory of diffusion, Analogies with momentum and heat transfer.MSH pp. 527-531. Mass transfer theories, two film theory. Mass transfer coefficients. MSH pp.542-544, 547-550. Operating line and equilibrium curve in mass transfer processes. Classification of mass transfer processes. Stages- and continuous operations.
  21. Gas absorption and adsorption. Principles of absorption. Adsorption in plate and packed towers. Common tower packing. GE. pp. 653-657, MSH pp. 565-568. Material balances. Operating line and equilibrium curve. Limiting gas-liquid ratio. Calculation of tower height. Number of transfer units, NTU, and height of transfer unit MSH pp576-582. Adsorption. Fixed-bed adsorbers. MSH pp. 839-840.
  22. Distillation, Principles of distillation. Vapor-liquid equilibrium relations. Boiling-point diagrams and x-y plots. Relative volatility of vapor-liquid systems. Equilibrium diagrams for ideal- and real systems. Azeotropes. GE. pp. 696-700. Simple distillation methods. Flash or equilibrium distillation. Simple batch or differential distillation. GE. pp. 700-704, MSH. pp. 663-665.
  23. Continuous distillation with reflux. Action on an ideal plate. Combination rectification and stripping. Material balance in plate columns. Overall material balances for two-component system. Net flow rate. Operating lines. Number of ideal plates, McCabe-Thiele method. Condition of feed. Feed line. Minimum number of plates. Minimum reflux. Optimum reflux ration. MSH pp. 666-682.
  24. Extraction. Liquid-liquid extraction. Single- stage liquid-liquid extraction processes. Equilibrium relations in extraction. MSH. pp. 772-779. GE.776-778. Extraction equipment. MSH. 772-778.
  25. Chemical reactors. Classification of reactors. Homogeneous and heterogeneous reactors. Batch- and continuous reactors. Tubular flow reactor, Continuous stirred tank reactor (CSTR) and CSTRs in series as frequently used. Chemical kinetics. Definition of reaction rate, order of reaction and rate constant. Influence of temperature, Arrhenius’ equation.
  26. Batch reactors, calculation of reaction time, basic design equation. Tubular flow reactors, basic design equations for tubular reactor. Residence time and space velocity. Continuous stirred tank reactor, design equations for continuous stirred tank reactor. Isothermal and adiabatic reactors.

[MSH] → W. L. McCabe, J. C. Smith, P. Harriot: Unit Operations of Chemical Engineering, Seventh Edition, McGraw-Hill International Edition, 2007.

[GE] → C. G. Geankoplis: Transport Processes and Separation Processes (Includes unit Operations), Forth Edition, Prentice Hall, 2008.

[EA] → R. L. Earle with M. D. Earle: Unit Operations in Food Processing.

[GU]→ L. Gulyás: Transport Equations of Chemical Engineering. University of Debrecen, 2009.

[FOG] →H. Scott Fogler: Elements of Chemical Reaction Engineering. Fourth Edition, Prentice Hall. 2008.

[COUL] →J. M. Coulson, J. F. Richardson: Chemical engineering. Volume three. Pergamon Press. 1979

Chemical Technology

(TKBE1111_EN, TKBE1112_EN, TKBE1113_EN)

  1. Chemical process systems. The laws of chemical technology, developments in technology, chemical technology systems, batch and continuous production.
  2. Energetics. Naturally occurring energy sources, energy demand, energy conversion facilities, energy management.
  3. Combustion techniques, elements of combustion techniques, possibilities for measuring temperature.
  4. Corrosion. Corrosion damage, corrosion types and formation.
  5. Corrosion protection. Active and passive corrosion protection, corrosion problems and solutions for the technologies studied.
  6. Water technology. Occurrence and uses of water, water purification.
  7. Water softening. Hardness, Water softening methods involving and without precipitates.
  8. Sulfur industry I. The use of sulfur, sulfur sources, Claus process, sulfur dioxide production.
  9. Sulfur industry II. Problems and solutions of the industrial production of sulfur trioxide, contact sulfuric acid process.
  10. Fertilizer, production of fertilizer. Role and significance of fertilizers. Materials of superphosphate production, superphosphate production and byproduct utilization.
  11. NitrogenindustryI. Structure of the nitrogen industry. Production and purification of synthesis gas.
  12. Nitrogen industry II. Problems and technological solutions of ammonia synthesis.
  13. Nitrogen industry III. Combustion of ammonia, nitric acid production.
  14. Nitrogen-containing fertilizers. Ammonium nitrate and urea production.
  15. Rock salt based industry. Brine electrolysis, membrane cell and mercury cell processes.
  16. Aluminum industry. Occurrence of aluminum, alumina production according to Bayer, the electrolysis of alumina, aluminum purification.
  17. Iron and steel production. Occurrence of iron, ores, ore substitutes. The types of iron, the blast furnace operation.
  18. Steel production. Types of steel, steel production.
  19. Coal. The classification of coal, coal formation, processing, components. Coal processing methods and products.
  20. Crude oil and natural gas. The oil and gas formation, classification, components.
  21. Natural gas processing methods. Cooled lean oil absorption method.
  22. Motor fuels I. The atmospheric distillation of crude oil and products. Properties of high-quality gasoline and diesel, octane number, cetane number.
  23. Motor fuels II. Increasing the volume and quality of motor fuels.
  24. Motor fuels III. Methyl tert-buthyl-ether and biodiesel production.
  25. Lubricants. Vacuumdistillation of pacura, lubricant types, the manufacture, uses.
  26. Pyrolysis of naphta I. Technological and thermodynamical basis of hydrocarbons cleavages.
  27. Pyrolysis of naphta II. The structure of pyrolyzer furnace, pyrolysis, separation of pyrogas, ethylene and propylene production.
  28. Second generation monomers. Vinyl chloride production.
  29. Aromatic raw materials and production. BTX fraction and its products.
  30. Carbon monoxide based synthesis.

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