Principles and Practice of Engineering Exam (PE) Chemical Engineering (PE Chemical) Syllabus

Chemical Engineering (PE Chemical) syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Chemical Engineering (PE Chemical) in Principles and Practice of Engineering Exam (PE), not a summary of it.

1. 1

   Mass and Energy Balances

   3 topics

   • Material Balances
     • Steady-state balances with and without reaction
     • Recycle, bypass, and purge
     • Combustion stoichiometry
   • Energy Balances
     • Enthalpy and heat capacity
     • Heats of reaction and formation
     • Combined mass and energy balances
   • Process Variables
     • Units, dimensions, and conversions
     • Pressure, temperature, and flow measurement
2. 2

   Thermodynamics and Phase Behavior

   3 topics

   • Chemical Thermodynamics
     • Equations of state
     • Fugacity and activity coefficients
   • Phase Equilibria
     • Vapor-liquid equilibrium
     • Raoult's and Henry's laws
   • Reaction Equilibrium
     • Equilibrium constants
     • Le Chatelier's principle
3. 3

   Transport, Separations, and Reactions

   3 topics

   • Fluid and Heat Transport
     • Pipe flow and pumps
     • Heat exchanger design
   • Mass Transfer and Separations
     • Distillation and absorption
     • Extraction and drying
   • Reaction Engineering
     • Reaction kinetics and rate laws
     • Batch, CSTR, and PFR design
4. 4

   Process Design, Control, and Safety

   3 topics

   • Process Control
     • Feedback control and tuning
     • Instrumentation and P&IDs
   • Process Safety
     • Hazard analysis (HAZOP)
     • Relief systems and overpressure protection
     • PSM and regulatory compliance
   • Economics and Optimization
     • Equipment sizing and costing
     • Process economics

Chemical Engineering (PE Chemical) flashcards for Principles and Practice of Engineering Exam (PE)

18 of 62 cards from the Chemical Engineering (PE Chemical) deck — real questions with worked answers.

1. State the general material balance equation for a system.

   $$\text{Accumulation} = \text{In} - \text{Out} + \text{Generation} - \text{Consumption}$$ For a steady-state process with no reaction, this reduces to $\text{In} = \text{Out}$.

2. How do you compute the degrees of freedom (DOF) for a material balance problem, and what does each result mean?

   $\text{DOF} = (\text{unknowns}) - (\text{independent equations})$. If $\text{DOF}=0$ the problem is exactly determined (solvable); if $\text{DOF}>0$ it is underspecified; if $\text{DOF}<0$ it is overspecified.

3. What is the difference between a tie component and a basis in material balance calculations?

   A basis is an assumed reference quantity (e.g., 100 mol feed) used to start the calculation. A tie component is a species that passes unchanged from one stream to another, letting you link stream flow rates directly.

4. Define recycle, bypass, and purge streams in a process flowsheet.

   Recycle returns material from a downstream point back upstream. Bypass diverts part of a feed around a unit. Purge removes a small stream to prevent accumulation of inerts or impurities in a recycle loop.

5. For a reactive system, define fractional conversion $X$ of a limiting reactant.

   $$X = \frac{n_{A,0} - n_A}{n_{A,0}} = \frac{\text{moles reacted}}{\text{moles fed}}$$ where $n_{A,0}$ is the initial moles of limiting reactant $A$ and $n_A$ the moles remaining.

6. Define yield and selectivity in a multi-reaction system.

   Yield $=\dfrac{\text{moles desired product formed}}{\text{moles reactant consumed (or fed)}}$. Selectivity $=\dfrac{\text{moles desired product}}{\text{moles undesired product}}$.

7. Write the steady-state open-system (flow) energy balance neglecting kinetic and potential energy.

   $$\dot{Q} - \dot{W}_s = \Delta \dot{H}$$ where $\dot{Q}$ is heat added, $\dot{W}_s$ is shaft work done by the system, and $\Delta\dot{H}$ is the enthalpy change of the streams.

8. How is the enthalpy change of a stream computed when there is no phase change or reaction?

   $$\Delta H = \int_{T_1}^{T_2} C_p \, dT$$ For constant heat capacity, $\Delta H = C_p (T_2 - T_1)$.

9. Define the standard heat of reaction $\Delta H_{rxn}^{\circ}$ in terms of heats of formation.

   $$\Delta H_{rxn}^{\circ} = \sum_{\text{products}} \nu_i \Delta H_{f,i}^{\circ} - \sum_{\text{reactants}} \nu_j \Delta H_{f,j}^{\circ}$$

10. State Hess's law and its significance for energy balances.

    The enthalpy change of an overall reaction equals the sum of enthalpy changes of its individual steps, because enthalpy is a state function and independent of path. This lets you compute $\Delta H_{rxn}$ from tabulated reactions/formation data.

11. What is the difference between higher heating value (HHV) and lower heating value (LHV)?

    HHV assumes the water produced in combustion is condensed to liquid (recovers latent heat); LHV assumes water remains as vapor. They differ by the heat of vaporization of the water formed: $\text{HHV} = \text{LHV} + n_{\ce{H2O}} \Delta H_{vap}$.

12. Convert gauge pressure to absolute pressure.

    $$P_{abs} = P_{gauge} + P_{atm}$$ where $P_{atm} \approx 101.3\ \text{kPa} = 14.7\ \text{psi}$ at sea level.

13. Define the relationship between mole fraction $x_i$ and mass fraction $w_i$.

    $$w_i = \frac{x_i M_i}{\sum_j x_j M_j}, \qquad x_i = \frac{w_i / M_i}{\sum_j w_j / M_j}$$ where $M_i$ is the molar mass of species $i$.

14. Define specific gravity and relate it to density.

    $$\text{SG} = \frac{\rho_{\text{substance}}}{\rho_{\text{reference}}}$$ The reference is usually water at $4^{\circ}\text{C}$ ($\rho = 1000\ \text{kg/m}^3$) for liquids/solids.

15. Distinguish between dry-bulb temperature, wet-bulb temperature, and dew point.

    Dry-bulb is the actual air temperature. Wet-bulb is the temperature reached by evaporative cooling at saturation. Dew point is the temperature at which the air becomes saturated and condensation begins. They are equal only at 100% relative humidity.

16. Write the ideal gas law and define each variable.

    $$PV = nRT$$ $P$ = absolute pressure, $V$ = volume, $n$ = moles, $T$ = absolute temperature, $R$ = universal gas constant ($8.314\ \text{J/(mol·K)}$).

17. State the first law of thermodynamics for a closed system.

    $$\Delta U = Q - W$$ The change in internal energy equals heat added to the system minus work done by the system.

18. Write the combined first and second law (fundamental property relation) for internal energy.

    $$dU = T\,dS - P\,dV$$

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