PRC Chemical Engineer Licensure Examination

A stoichiometry calculation is required for the complete combustion of propane (C3H8). How many moles of oxygen (O2) are required to completely burn 2.5 moles of propane gas?

• A5.0 moles
• B10.0 moles
• C12.5 moles
• D15.0 moles

Which of the following elements has the highest first ionization energy?

• ASodium (Na)
• BChlorine (Cl)
• CArgon (Ar)
• DPotassium (K)

In coordination chemistry, what is the crystal field splitting d-orbital configuration for a high-spin octahedral complex of Fe(II) (d6 configuration)?

• At2g4 eg2
• Bt2g6 eg0
• Ct2g3 eg3
• Dt2g5 eg1

The van der Waals equation of state accounts for deviations from ideal gas behavior. What physical phenomena do the parameters 'a' and 'b' represent, respectively?

• AIntermolecular attractive forces and molecular volume
• BMolecular volume and intermolecular attractive forces
• CGas molecular weight and temperature deviations
• DCollisional frequency and average kinetic energy

A water sample contains 120 mg/L of Ca2+ ions and 36 mg/L of Mg2+ ions. What is the total hardness of the water sample expressed in mg/L as CaCO3? (Molar masses: Ca = 40.0 g/mol, Mg = 24.3 g/mol, CaCO3 = 100.1 g/mol)

• A156 mg/L as CaCO3
• B300 mg/L as CaCO3
• C448 mg/L as CaCO3
• D600 mg/L as CaCO3

What is the IUPAC name for the organic compound CH3-CH(CH3)-CH(C2H5)-CH2-CH3?

• A2-methyl-3-ethylpentane
• B3-ethyl-2-methylpentane
• C3-isopropylpentane
• D2,3-diethylbutane

Which of the following reaction conditions favors an SN2 mechanism over an SN1 mechanism for a nucleophilic substitution reaction?

• AUsing a tertiary alkyl halide substrate
• BUsing a polar protic solvent
• CUsing a strong nucleophile at a high concentration
• DConducting the reaction at low temperature with no nucleophile

According to Hückel's Rule, which of the following monocyclic conjugated compounds is aromatic?

• ACyclobutadiene
• BCyclooctatetraene
• CCycloheptatrienyl cation (tropylium ion)
• DCyclopentadienyl cation

In electrophilic aromatic substitution, which of the following groups acts as a meta-director?

• A-OCH3 (Methoxy group)
• B-NO2 (Nitro group)
• C-NH2 (Amino group)
• D-CH3 (Methyl group)

Tollens' reagent (ammoniacal silver nitrate) is commonly used to distinguish between which two classes of organic compounds?

• AAlcohols and Ethers
• BAldehydes and Ketones
• CCarboxylic Acids and Esters
• DAlkanes and Alkenes

A gravimetric analysis is conducted to determine the sulfate content in a sample. The sulfate is precipitated as barium sulfate (BaSO4). What is the gravimetric factor for calculating the mass of sulfur (S) from the mass of BaSO4 precipitate? (Molar masses: S = 32.06 g/mol, O = 16.00 g/mol, Ba = 137.33 g/mol)

• A0.1374
• B0.4115
• C0.6860
• D1.000

When titrating a 0.10 M solution of acetic acid (a weak acid, Ka = 1.8 x 10^-5) with a 0.10 M solution of sodium hydroxide (a strong base), what is the pH characteristics of the solution at the equivalence point?

• AExactly 7.00
• BLess than 7.00
• CGreater than 7.00
• DCannot be determined without temperature

The solubility product constant (Ksp) of lead(II) chloride (PbCl2) is 1.7 x 10^-5. What is the molar solubility of PbCl2 in a 0.10 M NaCl solution? (Neglect complex ion formation)

• A1.7 x 10^-3 M
• B1.7 x 10^-4 M
• C1.6 x 10^-2 M
• D4.2 x 10^-6 M

A solution of a compound has an absorbance of 0.60 when measured in a 1.0 cm pathlength cell at a wavelength of 450 nm. If the molar absorptivity of the compound is 3.0 x 10^3 L/(mol*cm), what is the concentration of the compound?

• A2.0 x 10^-4 mol/L
• B5.0 x 10^-4 mol/L
• C1.8 x 10^3 mol/L
• D2.0 x 10^-3 mol/L

In thin-layer chromatography (TLC), how is the retention factor (Rf) calculated?

• ADistance traveled by the solvent front divided by distance traveled by the compound
• BDistance traveled by the compound divided by distance traveled by the solvent front
• CTime taken for the solvent to climb the plate divided by sample elution time
• DRatio of the mass of the compound to the mass of the stationary phase

The rate constant of a chemical reaction double when the temperature is increased from 300 K to 310 K. What is the activation energy (Ea) of the reaction in kJ/mol? (R = 8.314 J/(mol*K))

• A27.2 kJ/mol
• B53.6 kJ/mol
• C107 kJ/mol
• D44.5 kJ/mol

According to the Gibbs Phase Rule, how many degrees of freedom (F) does a system containing liquid water in equilibrium with its vapor have, assuming it is a pure single-component system?

• A0
• B1
• C2
• D3

For the electrochemical cell reaction: Zn(s) + Cu2+(aq) -> Zn2+(aq) + Cu(s) with standard cell potential Eo = 1.10 V. What is the cell potential (E) at 298 K when [Zn2+] = 1.0 M and [Cu2+] = 0.010 M? (R = 8.314 J/(mol*K), F = 96,485 C/mol)

• A1.04 V
• B1.16 V
• C0.98 V
• D1.22 V

For the gas-phase reaction N2(g) + 3 H2(g) <-> 2 NH3(g), how are the equilibrium constants Kp and Kc related at a temperature T?

• AKp = Kc * (RT)
• BKp = Kc * (RT)^-2
• CKp = Kc * (RT)^2
• DKp = Kc * (RT)^-1

Which of the following statements correctly describes the difference between Raoult's law and Henry's law?

• ARaoult's law applies to the solute in a dilute solution, while Henry's law applies to the…
• BRaoult's law applies to the solvent in a dilute solution, while Henry's law applies to th…
• CRaoult's law is for non-ideal mixtures, while Henry's law is exclusively for gas-solid sy…
• DRaoult's law assumes no vapor pressure for the solvent, while Henry's law assumes volatil…

The vapor pressure of water at 100°C is 760 mmHg. What equation should be used to estimate the vapor pressure of water at 120°C, assuming the heat of vaporization remains constant over this range?

• AGibbs-Helmholtz Equation
• BClausius-Clapeyron Equation
• CAntoine Equation
• DVan der Waals Equation

What is the critical micelle concentration (CMC) of a surfactant?

• AThe concentration at which surfactants start to precipitate from solution
• BThe concentration at which micelles begin to form and surface tension becomes nearly cons…
• CThe temperature at which surfactant solubility increases dramatically
• DThe maximum concentration of surfactant that can dissolve in water

In crystallography, what are the Miller indices of a plane that intercepts the x-axis at 1, the y-axis at 2, and is parallel to the z-axis?

• A(1 2 0)
• B(2 1 0)
• C(1 1 0)
• D(2 2 0)

Which of the following crystal structures has the highest atomic packing factor (APF) and coordination number?

• ASimple Cubic (SC)
• BBody-Centered Cubic (BCC)
• CFace-Centered Cubic (FCC)
• DHexagonal Close-Packed (HCP) - coordination number only

On a typical stress-strain curve for a ductile metallic material, what does the ultimate tensile strength (UTS) represent?

• AThe stress at which plastic deformation first begins
• BThe maximum stress that the material can withstand before necking and fracture
• CThe slope of the elastic region of the curve
• DThe strain at which the material breaks

In the iron-carbon (Fe-Fe3C) phase diagram, what is the name of the phase that represents a solid solution of carbon in body-centered cubic (BCC) iron stable at room temperature?

• AAustenite (gamma-iron)
• BFerrite (alpha-iron)
• CCementite (Fe3C)
• DMartensite

A wastewater sample has an initial dissolved oxygen (DO) of 8.0 mg/L. After a 5-day incubation at 20°C with a dilution factor of 1:50 (2% sample), the final DO of the mixture is 3.5 mg/L. What is the 5-day biochemical oxygen demand (BOD5) of the wastewater sample? (Assume seed correction is negligible)

• A4.5 mg/L
• B90 mg/L
• C225 mg/L
• D400 mg/L

Which of the following greenhouse gases has the highest Global Warming Potential (GWP) over a 100-year time horizon?

• ACarbon Dioxide (CO2)
• BMethane (CH4)
• CNitrous Oxide (N2O)
• DSulfur Hexafluoride (SF6)

Eutrophication in aquatic bodies is primarily caused by an excessive concentration of which nutrients?

• ACalcium and Magnesium
• BPhosphates and Nitrates
• CSodium and Chlorides
• DCarbonates and Bicarbonates

In the activated sludge process of wastewater treatment, what is the Sludge Volume Index (SVI) used to evaluate?

• AThe rate of oxygen consumption by microorganisms
• BThe concentration of toxic chemicals in the influent
• CThe settling characteristics of the activated sludge in the secondary clarifier
• DThe ratio of food (BOD) to microorganisms (MLSS)

A distillation column separates a feed containing 40 mol% benzene and 60 mol% toluene. The distillate contains 95 mol% benzene, and the bottoms contain 5 mol% benzene. If the feed rate is 100 kmol/h, what is the flow rate of the distillate?

• A35.0 kmol/h
• B38.9 kmol/h
• C44.4 kmol/h
• D50.0 kmol/h

Propane (C3H8) is burned completely with 20% excess air. What is the air-to-fuel mole ratio for this combustion process?

• A23.8
• B28.6
• C5.0
• D6.0

In a process flow diagram, a process stream is split into a bypass stream and a main reactor feed stream. What is the primary purpose of employing a bypass stream in industrial process plants?

• ATo increase the overall conversion of the reactant in the reactor
• BTo control the composition or temperature of the final mixed exit stream
• CTo prevent catalyst deactivation by reducing reactor pressure
• DTo eliminate the need for purge streams in recycle loops

How much heat (in kW) is required to raise the temperature of 2.0 kg/s of liquid water from 25°C to 85°C? (Specific heat capacity of water = 4.184 kJ/(kg*K))

• A8.37 kW
• B251 kW
• C502 kW
• D711 kW

A heat engine operates between a hot reservoir at 600 K and a cold reservoir at 300 K. What is the maximum theoretical thermal efficiency of this engine?

• A33.3%
• B50.0%
• C66.7%
• D100%

The compressibility factor (Z = PV/RT) is used to quantify deviations from ideal gas behavior. What does a Z value less than 1 indicate about the gas?

• AAttractive forces dominate, making the gas easier to compress than an ideal gas
• BRepulsive forces dominate, making the gas harder to compress than an ideal gas
• CThe gas has reached its critical pressure and temperature
• DThe gas behavior matches the ideal gas law perfectly

The Gibbs-Duhem equation relates changes in chemical potential, temperature, and pressure for mixtures. For a binary system at constant temperature and pressure, which of the following is the correct representation?

• Ax1*d(mu1) + x2*d(mu2) = 0
• Bd(mu1) + d(mu2) = 0
• Cx1*d(ln(gamma1)) - x2*d(ln(gamma2)) = 0
• Dx1*P*d(mu1) + x2*T*d(mu2) = 0

A vapor-compression refrigeration cycle operates with a cooling load of 15 kW. If the compressor requires 5.0 kW of electrical power input, what is the Coefficient of Performance (COP) of the refrigerator?

• A0.33
• B2.0
• C3.0
• D4.0

A composite furnace wall consists of 10 cm of firebrick (k = 1.0 W/(m*K)) and 20 cm of insulating brick (k = 0.10 W/(m*K)). What is the total thermal resistance per unit area (m²*K/W) of this composite wall?

• A0.30 m2*K/W
• B2.1 m2*K/W
• C3.0 m2*K/W
• D11 m2*K/W

A counter-current heat exchanger cools a hot fluid from 120°C to 80°C using a cold fluid that enters at 30°C and leaves at 60°C. What is the Logarithmic Mean Temperature Difference (LMTD) for this heat exchanger?

• A54.9°C
• B50.0°C
• C45.0°C
• D60.0°C

What is the dimensionless Nusselt number (Nu) defined as in convective heat transfer?

• ANu = h*L / k
• BNu = C_p*mu / k
• CNu = rho*v*L / mu
• DNu = h / (rho*v*C_p)

A small blackbody sphere of surface area A at a temperature of 500 K radiates heat to the surrounding environment at 300 K. According to the Stefan-Boltzmann law, what is the net radiation heat loss rate proportional to?

• A(500 - 300)
• B(500^2 - 300^2)
• C(500^4 - 300^4)
• Dln(500 / 300)

A gas mixture of A and B undergoes steady-state equimolar counterdiffusion. The total pressure is 1.0 atm and the temperature is 298 K. The partial pressure of A is 0.15 atm at point 1 and 0.05 atm at point 2, separated by a distance of 0.10 m. If the diffusion coefficient Dab is 2.0 x 10^-5 m²/s, what is the molar flux of A (Ja)? (R = 8.206 x 10^-5 m³*atm/(mol*K))

• A8.2 x 10^-4 mol/(m2*s)
• B8.2 x 10^-3 mol/(m2*s)
• C8.2 x 10^-2 mol/(m2*s)
• D8.2 x 10^-5 mol/(m2*s)

In mass transfer, what is the Schmidt number (Sc) physically defined as?

• ARatio of momentum diffusivity (kinematic viscosity) to mass diffusivity
• BRatio of convective mass transfer to molecular mass transfer
• CRatio of thermal diffusivity to mass diffusivity
• DRatio of inertial forces to surface tension forces

In the design of packed absorption columns, how does the Height of a Transfer Unit (HTU) relate to the total height of the packing (Z)?

• AZ = HTU * NTU
• BZ = HTU / NTU
• CZ = NTU / HTU
• DZ = HTU + NTU

Which of the following mass transfer operations represents leaching?

• ASeparating a liquid mixture by selective evaporation using a gas stream
• BExtracting a soluble solute from a solid matrix using a liquid solvent
• CRemoving volatile components from a liquid using steam
• DTransferring a component from a gas mixture into a liquid absorbent