AIChE Chemical Engineering Jeopardy Practice Exam

These questions are part of the practice quiz. Start practicing

• How many times do the minute and hour hands overlap in a 24-hour day?
• A Grignard reaction involves which type of reagent reacting with a carbonyl compound?
• Which pair of states were admitted in 1912 as the 47th and 48th states?
• Hyundai is a major automobile manufacturer from which country?
• The Antoine equation is commonly used to estimate:
• In liquid extraction, the two phases are commonly called the extract phase and the _______.
• Who voiced Dory in Finding Nemo?
• Which organization publishes safety data values used by industrial hygienists for exposure assessments?
• The Mary Tyler Moore Show was set in which city?
• In the expression -cos(x) + C, what does C represent?
• What is a cold front?
• Knudsen diffusion occurs predominantly in pores where the diameter is smaller than the mean free path of gas molecules.
• How many years are in a score?
• In an ideal gas, the speed of sound is given by a = sqrt(gamma R T / M). Which of the following is the correct expression for a?
• Which field best describes Robert Langer's notable work?
• Which statement completes the dust explosion pentagon?
• What is the law of cosines?
• Sandy Cheeks is originally from which state?
• Autoignition temperature is defined as the minimum temperature at which a substance does what?
• February 15th is celebrated as which day in the show?
• The sequence 0, 1, 1, 2, 3, 5, 8, ... is named after which Italian mathematician?
• Which method helps mitigate water hammer in piping systems?
• Lenz's Law states that the induced current's magnetic field does what to oppose changes in flux?
• The 1970 OSHA Act was signed into law by which U.S. president?
• What does the Central Dogma of Molecular Biology describe?
• In Cyber Chase, what is the name of the villain the kids battle?
• Conduction in concentric spheres models heat transfer in which geometry?
• IChemE oversees awarding some of the best chemical engineers around the world with their yearly Global Awards.
• In mathematics, which factorial equals 120?
• Which expansion corresponds to the acronym FOPDT?
• Port Wentworth is located in which state?
• The 2023-24 season of The Simpsons is which numbered season?
• Which city hosted the first AIChE Annual Conference in 1908?
• Which pump type requires a relief valve on its discharge side?
• What is the product of beta decay of carbon-14?
• Which expression represents continuously compounded interest growth of principal P at rate r over time t?
• Which national park located in Alaska is the largest by area?
• Which option is not a standard method of calculating interest?
• Maude Flanders is best described as which character's wife?
• Which expression represents Kirchhoff's current law at a junction?
• What is a patent?
• A river's looping bend is called what?
• What is caffeine?
• Saul Goodman received his law degree from which university?
• The Damköhler number is the ratio of the rate of reaction to the rate of mass transfer. Which statement best describes its interpretation?
• NFPA Class D fires are used for which materials type?
• A constant-volume process is also called which term?
• Which chemist introduced the thermodynamic concept of activity and coined the term fugacity?
• Which name does Princess Aurora use to conceal her identity in Sleeping Beauty?
• The discovery of radioactivity by Becquerel involved the effect of uranium salts on which material?
• In the explosive data equation, the volume exponent is what?
• Which term defines the legal maximum average exposure to a chemical in a workday?
• The minimum number of theoretical plates for binary distillation at total reflux is determined by which concept?
• What is differentiation?
• The Bernoulli equation describes which quantities along a streamline?
• Who is Dr. Strangelove?
• Which city is associated with the initial outbreak of SARS-CoV-2 in December 2019?
• Buoyancy force is described by which principle?
• Who is Lady Gaga?
• In a steady-state bioreactor, which parameter can be determined from the oxygen transfer equation?
• The coexistence equation in a binary system is derived from which fundamental relation?
• Which separation method consumes approximately 40 percent of the total energy used in chemical and petroleum refining industries?
• Freon was banned primarily to protect which atmospheric layer?
• Which quantity is used to express the rate of mass transfer per unit area in a flowing system?
• What is the function of a pump in fluid systems?
• What is Monel?
• What best defines a beta particle?
• In distillation, how is the boilup ratio defined?
• Which RNA type carries the genetic message from DNA to the ribosome for protein synthesis?
• Which scientists developed the inactivated and attenuated polio vaccines that came into commercial use in 1955 and 1961, respectively?
• In which animated series do Mermaid Man and Barnacle Boy appear as retired superheroes?
• The Langmuir isotherm expresses the amount adsorbed q as a function of partial pressure P. Which form represents the Langmuir expression?
• A relief valve is primarily used to prevent what hazardous condition?
• Frances Arnold won the Nobel Prize in Chemistry in which year?
• The Thiele modulus is useful in predicting reactor behavior when what condition applies?
• In a packed-bed contactor, which statement best describes the function of packing material?
• Fleming's discovery of penicillin in 1928 arose from which laboratory occurrence?
• In turbulent pipe flow, the heat transfer coefficient h is generally proportional to Reynolds number raised to which power?
• Which three factors mainly determine the capital cost of a piece of equipment at a given time?
• Which equation describes Michaelis-Menten kinetics?
• Kg^-1 m^-2 s^4 A^2 is the base SI unit for which quantity?
• Which MIT professor is a widely recognized and cited researcher in medical biotechnology and participated in the founding of over 40 biotechnology companies including Moderna?
• What is trinitrotoluene commonly known as?
• Which statement correctly defines average speed?
• Vibranium is widely recognized for being used in Captain America's shield and whose cybernetic arm?
• What is the complete genus and species name of the bacterium most used in recombinant protein production?
• Which color indicates flammability in the NFPA diamond?
• Filtration is the method used to separate solids from fluids by interposing a medium through which only the fluid can pass. Which term describes this process?
• CSTR stands for which of the following?
• What are faults?
• Which statement best describes the Grashof number?
• Which enzyme catalyzes the conversion of ADP and inorganic phosphate to ATP?
• In fault tree analysis, which logic gate is used to indicate that all listed failures must occur to cause the top event?
• In the US customary system, how many fluid ounces are in a pint?
• In which city was the first human case of SARS-CoV-2 infection identified in December 2019?
• What best describes a purge stream in a chemical system?
• Margaret ('Hot Lips') Houlihan is a character from which series?
• Westview, New Jersey is most accurately described as what in the MCU?
• In Henry's Law for a dilute solute, which quantities are connected by the law?
• Salvage value is typically treated in project evaluation as what?
• What AIChE milestone did Diane Dorland achieve in 2003?
• Which amendment protects against unreasonable searches and seizures by the government?
• What is molybdenum?
• When is a mechanical energy balance typically written?
• Helicobacter pylori causes which condition?
• According to Boyle's Law, at constant temperature, what happens to pressure when volume is decreased?
• Who invented the battery in 1800?
• The degrees of unsaturation for C10H13BrO2 is which value?
• Pressure piling is the phenomenon that increases local pressure in which context?
• The Clausius-Clapeyron equation relates vapor pressure to temperature. In this context, which quantity changes with temperature?
• Which act led to the creation of both OSHA and NIOSH?
• In the Stokes-Einstein relation, which parameter increases the diffusion coefficient when raised?
• In a first-order dynamic system, the time constant is defined as the time required to reach what percent of the final output?
• Which receptor on human cells is used by SARS-CoV-2 to enter the cell?
• The Peng-Robinson equation of state is widely used in which industry for phase behavior predictions?
• What is the Hagen-Poiseuille equation for pressure drop in a laminar pipe?
• Which metal is contained in heme to enable oxygen transport?
• The Occupational Safety and Health Act of 1970 created OSHA and which related organization responsible for research and recommendations on safety and health?
• Who shot Mr. Burns in the two-part episode?
• What does TLV-TWA stand for in occupational exposure terminology?
• Which British physicist discovered the electron?
• In non-steady state diffusion from a constant source, the concentration's dependence on distance is the same as its dependence on what power of time?
• Which organization was created by the 1970 OSH Act to develop new knowledge in the field of occupational safety and health and to transfer that knowledge into practice?
• Which body certifies the Electoral College results in the United States?
• In the context of Infinity Stones, what do '6' and the soul stone refer to?
• Complex poles lead to which damping type?
• In a cash flow diagram, the sign convention for positive values commonly indicates which of the following?
• The Bernoulli equation applies to which type of flow along a streamline?
• How many neutrons are in the isotope Cl-37?
• In the design of an aerated bioreactor, which dimensionless number is used to determine mixer power?
• Who is Drake?
• Which organism is associated with causing stomach ulcers?
• The salvage value of a plant is best described as:
• Angela Merkel served as Chancellor of Germany beginning in which year?
• Which statement best describes the van Deemter plot in chromatography?
• Erwin Schrödinger was a physicist from which country?
• In reactor design, recycle means:
• Entropy (S) is best described as:
• In The Simpsons, who is humorously described as the nuclear safety inspector at the nuclear power plant?
• A Levenspiel plot graphs FA0/−rA versus X. What does this plot primarily help determine?
• Which thermally resistant bacterium is used as the model organism for designing heat sterilization systems for growth media?
• LASER stands for which phrase?
• The Pitot tube is used to measure fluid velocity and consists of a narrow tube facing upstream and connected to a manometer. What principle does it employ?
• Baeyer-Villiger oxidation of a cyclic ketone yields which type of product?
• In differential equations describing a finite domain, what term provides the extra restraints that close the system?
• What is the name of the human cell surface receptor to which the SARS-CoV-2 spike protein binds to initiate infection?
• These are long, thin filaments that protrude from the cell surface and enable bacteria to move.
• Which statement accurately describes the plug flow reactor flow?
• What is a cash flow diagram?
• What is a plasmid?
• What characterizes a detonation compared to other explosions?
• Pain and Panic are which characters in Disney's Hercules?
• Which national park contains the highest waterfall in the contiguous United States?
• 626 is the experiment number assigned to Stitch in Lilo & Stitch.
• Assuming each question has an equal chance to contain the Daily Double, what is the probability of selecting the Daily Double on a single question from a set of 30 questions?
• What device measures temperature using two dissimilar conductors?
• Lyme disease is primarily transmitted by which vector?
• Freon, formerly used in refrigerators and air conditioners, belongs to which class of chemical compounds?
• In what year did Joseph Priestley discover oxygen?
• What is the Mach number?
• Which statement defines an oxidizer?
• Who is Donald Glover?
• What is the Laplace Transform of f(t)?
• Pili are structures necessary for conjugation.
• Saccharomyces cerevisiae is the most used yeast species in commercial ethanol production. In that context, what is the primary product of this process?
• In Stokes flow, inertial forces are negligible compared to viscous forces. Which statement best describes this regime?
• What is the number of fluid ounces in a pint?
• The Diesel cycle comprises which sequence of processes?
• What is heme?
• Which statement expresses Boyle's Law?
• In bioprocessing, what does KLa represent?
• Which statement about 3-way solenoid valves is true?
• The eutectic point on a phase diagram is the point where what occurs?
• Which valve type should be used when a large back pressure is present?
• What was Saul Goodman’s name prior to becoming Saul?
• In ABE fermentation, A, B, and E stand for which compounds?
• Which statement accurately describes the NFPA hazard diamond layout?
• In substrate inhibition, how does enzyme activity respond to increasing substrate concentration at high levels?
• In what year was AIChE's Center for Chemical Process Safety founded?
• The 1990 federal legislation that authorized the CSB is the Clean Air Act Amendments of 1990. Which act is correct?
• Which statement correctly identifies the acronym FOPDT in process dynamics?
• TNT is primarily used as what?
• What is a manometer?
• Who discovered radioactivity?
• Ross Geller is a character from which TV show?
• Which gas is the heaviest among the listed elements?
• Which control strategy uses sensor feedback to minimize the difference between the process variable and a desired setpoint?
• In 2-hexene, where is the carbon-carbon double bond located?
• In the chemical concentration equation for non-steady state diffusion from a constant source, A(x,t) equals which expression?
• The Niagara River connects which two Great Lakes?
• The February 3, 2023 derailment in East Palestine, Ohio resulted in the release of which hazardous chemical?
• In the equation AX = λX, what is X called?
• Which physicist is associated with the entropy relation S = k log W?
• The huge explosion at a sugar refinery in February 2008 that resulted in 14 deaths occurred in which city?
• In DNA, adenine pairs with which base?
• Which country is a close second to the United States in chemical production?
• Which dimensionless number is used to describe convective mass transfer relative to diffusion in mass transfer analysis?
• Which RNA type forms the core structural and catalytic component of ribosomes?
• Adding enough recycle to a plug-flow reactor (PFR) to alter flow behavior tends to produce which reactor behavior?
• Which statement about degrees of unsaturation is correct?
• Which physicist is best remembered for the Schrödinger cat thought experiment?
• The Schmidt Number is defined as the ratio of what to what?
• Which insect was the first living creature sent into space?
• What does the acronym HAZWOPER stand for?
• Which equation models enzyme kinetics with Vmax and Km?
• Which diagram is specifically used to depict process equipment with interconnected instrumentation?
• In diffusion, what does the diffusion coefficient DAB represent?
• What is a unit operation in chemical engineering?
• Which property explains why droplets bead up on a non-wetting surface?
• Activation energy is defined as
• Dew point temperature is defined as:
• Fool's gold is the common name for which mineral?
• Which description correctly defines the moment of inertia?
• What is benzene?
• Which statement describes friction most accurately?
• Oxidation is defined as which?
• Which statement about distillation is true?
• In steady-state diffusion into a sphere, the center is defined as the location where the concentration gradient is steepest. Which option best represents the center?
• Which statement best defines the Miranda rights?
• Which statement best describes a Grignard reaction?
• What gas is produced by mixing household bleach with vinegar?
• Which word is formed by concatenating the chemical symbols B, O, and Ne?
• In Phase I clinical trials, how many healthy volunteers are typically used to determine the safety of a drug?
• Iron is the second most common metal in the Earth's crust and is used to catalyze which process?
• What is Moe's Tavern?
• Which pathway is primarily responsible for carbon dioxide fixation in photoautotrophs and chemolithotrophs?
• A balanced bellows spring loaded device is used to address which condition in systems experiencing large backpressure?
• In a Diels-Alder reaction, which component acts as the diene?
• The Flintstones lived in which city?
• In air used for combustion calculations, the mole ratio of nitrogen to oxygen is commonly expressed as what value?
• Sphericity is a measure of how close an irregular object is to which geometry?
• What is a meander?
• Which children's show stars Tinky-Winky, Dipsy, Laa Laa and Po?
• What is a cash-flow diagram used for?
• The ammonium nitrate explosion described as occurring at a storage facility in April 2013 happened in which location?
• In an isothermal process, which property remains constant?
• L'Hôpital's rule is used to evaluate limits that yield which indeterminate forms?
• Mass flux is defined as which physical quantity?
• January 6th, 2021 is notable for what event?
• Who is the only person to have served as both President and Chief Justice of the United States?
• Sacagawea translated for which pair of explorers on the expedition?
• What does TSCA stand for?
• Baeyer-Villiger oxidation converts ketones to what type of compound?
• In a chemostat, the dilution rate D equals the cellular growth rate. Which statement best describes D?
• If Da is much greater than 1, which process dominates the overall rate?
• Sacagawea is best described as which of the following?
• The Langmuir adsorption model assumes adsorption sites are ...
• The Niagara River connects which pair of Great Lakes?
• Audi is a luxury automobile brand from which country?
• Which type of enzyme inhibition is demonstrated by substrate inhibition, where high substrate concentrations decrease enzyme activity?
• Which parameter is the most widely controlled parameter in the chemical process industry?
• What is adenine?
• Which RNA type functions as an adaptor to deliver specific amino acids during translation?
• An explosion is defined as which of the following?
• Which animal is the central character in Zoboomafoo?
• In the two-part episode, who shot Mr. Burns?
• Which uranium isotope is commonly used as reactor fuel due to fissile nature?
• In which year did Thomas Edison develop the first thermal power station in the United States?
• In which city was the 2022 AIChE Annual Student Conference held?
• The F.U.N. Song is associated with which animated series?
• Which statement about molybdenum in steel is true?
• Elements number 98 and 99 (Bk and Cf) were discovered at UCRL. With which university is UCRL associated?
• The Pfizer COVID-19 vaccine consists of which material inside lipid nanoparticles?
• Which chemical was released during the East Palestine derailment?
• The Froude number is defined as the ratio of inertial forces to gravitational forces.
• The base for natural logarithms is which number?
• What is the primary survival advantage provided by bacterial spores?
• Absorption, or a scrubber, removes components from a rising gas by contacting it with a falling liquid. This process is known as what?
• A batch process is best described as which of the following?
• How many acres are there in a square mile?
• In enzyme inhibition, which type cannot be overcome by increasing substrate concentration?
• Which expression corresponds to the ISE performance criterion?
• Which business leader was nicknamed 'Neutron Jack' for eliminating employees while leaving buildings intact?
• What is salvage value?
• Betty Rubble is a character from which animated series?
• NIOSH stands for which phrase?
• What is a monoclonal antibody?
• In rheology, a Bingham plastic behaves as a solid until which threshold is exceeded?
• Which statement best defines an environmental hazard?
• The Diels-Alder reaction is a [4+2] cycloaddition forming what kind of ring?
• A positive displacement pump requires what on its discharge side?
• In liquid-liquid extraction, which term describes the phase that is not the extract and remains after extraction?
• 626 refers to the experiment number of Stitch in Lilo & Stitch.
• Which statement best describes Escherichia coli in biotechnology?
• The Fanning friction factor is usually a function of which two dimensionless parameters?
• Rust is the common name for which compound?
• NFPA is the abbreviation for which organization?
• Derivative control action: Too much will cause which type of closed-loop response?
• Amagat's Law is best described as which statement about gas mixtures?
• What are the five factors that constitute the dust explosion pentagon?
• Under STP conditions, what is the approximate molar volume of an ideal gas in liters per mole?
• Who is Derek Chauvin?
• Pollination is the process by which pollen is transferred from the male reproductive organ to what structure in a flower?
• Which scientist published the law of induction in 1831?
• What is the mean free path?
• Equimolar counterdiffusion is defined by Na = -Nb. Which of the following expresses this relation?
• The expression -cos(x) + C is the indefinite integral of which function?
• Dew-point temperature is defined as the temperature at which first liquid droplets form when a vapor is cooled at which condition?
• Which insect is responsible for the spread of African Trypanosomiasis (sleeping sickness)?
• What is the most produced industrial chemical in the world?
• If the reflux ratio is increased in a simple distillation column, what is the typical effect?
• ERPG-1 defines which of the following?
• The ratio of thermal diffusivity to mass diffusivity is designated by which dimensionless number?
• When are Miranda warnings typically required to be read?
• Teratogens are substances known to have the capability to cause malformations to an embryo or fetus.
• Which option is not part of the Diesel cycle?
• Which term is defined as the hazard level immediately dangerous to life and health?
• IDLH stands for which term in occupational safety?
• Which of the following is NOT a named fictional character listed in the source material?
• At what temperature is the density of water equal to 1 g/mL?
• Which Harvard chemist reportedly flunked organic chemistry?
• Which state was admitted as the 48th state?
• Complete the line 'N is for __________' from the F.U.N. Song.
• Which state is the smallest US state by land mass?
• Which particles are the most abundant with mass in the universe?
• What is a common use of the Laplace transform in engineering analysis?
• In what year was the smallpox vaccine developed by Edward Jenner?
• Which antibiotic was discovered in 1928 by Sir Alexander Fleming due to a laboratory contaminant?
• Picric acid is the common name for which compound?
• What sentence did Derek Chauvin receive for the murder of George Floyd?
• Which term is used for the large vessel where bioreactors are used and fermentation occurs, also called fermenter?
• Which equation relates the natural log of vapor pressure ratio to temperature difference during phase transitions?
• What is variance?
• In an SN2 reaction, which statement correctly describes the mechanism?
• What describes a fluidized bed reactor?
• At low Reynolds number, which equation relates the diffusion coefficient of spherical particles to temperature, viscosity, and particle radius?
• Frances Arnold Nobel Prize 2018 for her work on directed evolution.
• The polio vaccine developed by Jonas Salk is which type?
• Which line is associated with Homer's high school yearbook quote?
• Which year was the Lautenberg Act signed into law?
• What is the Gilliland correlation?
• Which type of enzyme inhibition is demonstrated by competitive binding to the active site?
• What is the last name of Craig and Betsy, the couple Saul Goodman pursues in season 1?
• A decoupler in a control loop is used to:
• What best describes the power number in mixing?
• In NFPA fire safety labeling, which hazards correspond to the blue, red and yellow sections respectively?
• Which of the following is NOT among the three main factors determining equipment capital cost?
• Current AIChE president (as of 2023)?
• What is the form of nucleic acid in SARS-CoV-2?
• BLEVE is the acronym for which phrase?
• The Heck reaction is a palladium-catalyzed cross-coupling that forms what product from aryl or vinyl halides and alkenes?
• Monel is a trademark name for which family of alloys?
• What type of mammalian cells are commonly used in recombinant DNA technology to produce monoclonal antibody medications?
• The genus of bacteria that cause anthrax.
• Who developed the first thermal power station in the United States in 1882?
• Which character performs the song 'Kiss the Girl' in The Little Mermaid?
• Which dimensionless number is used to determine whether pipe flow is laminar or turbulent?
• The Jungle is a famous novel by which author, and what issue does it highlight?
• The Lineweaver-Burk plot is a double reciprocal plot of which variables?
• In a distillation setup, what is the name of the vessel that collects the distillate after condensation?
• Lenz's Law describes the direction of induced emf and current. Which statement is correct?
• Which law states that the volume of a gas mixture is the sum of the pure component volumes?
• What is the Design Institute for Emergency Relief Systems (DIERS)?
• In a Grignard reaction, reacting a Grignard reagent with acetone produces what type of alcohol after aqueous workup?
• The Soul Stone is one of the Infinity Stones.
• Which statement best characterizes a Bingham plastic?
• Picric acid is best classified as which type of chemical compound?
• What is described as the only way to prevent a sea bear attack?
• The 50-50 split in the United States Senate was achieved as a result of elections in which state?
• Feedback control is defined as a control that uses which elements to set the manipulated variable?
• What is a Laplace Transform?
• Friends was set in which city?
• Which compound is an acceptable alternative to sodium fluoride for water fluoridation?
• The Mollier diagram is named after which person?
• In ignition terminology, what does AIT stand for?
• What is Frank Ocean's real name?
• Which insect is famous for cannibalistic mating behavior?
• What is the Modified Accelerated Cost Recovery System?
• Michaelis-Menten kinetics describes what?
• Which description best defines a batch chemical process?
• Zoboomafoo is best described as which of the following?
• On a Levenspiel plot, what is plotted on the vertical axis?
• ATP synthase catalyzes the formation of ATP from ADP and inorganic phosphate. Which option lists the most accurate descriptor of this enzyme's action?
• What is the damping factor?
• Which molecule is bent due to two lone pairs on the central atom?
• Which character is the fox that steals items from Dora the Explorer?
• Which equation has the form ln(Psat) = A - B/(T+C)?
• Which cellular structure is primarily responsible for locomotion?
• Which state was the first to be admitted to the United States on December 7, 1787?
• Autotrophs are organisms that primarily use which carbon source?
• The city and year of the first AIChE Annual Conference?
• Which dimensionless number relates to diffusion processes in heat and mass transfer, being the ratio of thermal diffusivity to mass diffusivity?
• In a one-dimensional heat conduction problem, the boundary condition δT/δx = 0 corresponds to what type of surface?
• One atmosphere corresponds to how many millimeters of mercury?
• Great Smoky Mountains National Park?
• In steady-state diffusion into a sphere, the center is defined as the location where the concentration gradient is steepest. Which option best describes this?
• Which statement is true about baking soda?
• A simplified version of which separation process is seen in a coffee or tea maker?
• Which expression represents the van der Waals equation of state?
• ERPG-1 stands for which term?
• How many US states border Mexico?
• The Wittig reaction employs which reagent to convert aldehydes or ketones into alkenes?
• An azeotropic mixture has a vapor that has the same composition as the liquid when boiling. True or False?
• What is a Lineweaver-Burk plot used for?
• What is Iron Man in the Marvel Cinematic Universe?
• Which metal is produced by the Kroll process?
• Slack flow is a type of flow that can occur when the gravitational driving force exceeds full pipe friction loss. In what kind of routing does this typically occur?
• Molybdenum is added to low-alloy steels to increase which property?
• Mothballs can be made of paradichlorobenzene or which other chemical?
• In the Stefan-Boltzmann law, what does the symbol σ represent?
• Which statement about saturation kinetics is true?
• The refinery fire in Richmond, California in August 2013 was triggered by what?
• Immobilized enzyme reactors are also known as what?
• Layer of Protection Analysis is used to assess what?
• Which control strategy is used to anticipate disturbances before the process output changes?
• What frequency does the United States grid use for AC power?
• What is the Blasius equation that describes the steady two-dimensional boundary layer stream function?
• What is The Treehouse of Horror?
• Which equation accounts for molecular size and intermolecular forces when modeling gases?
• In 1892 this became the first virus to be discovered.
• Vmax is proportional to enzyme concentration.
• In distillation design, what is the reflux ratio?
• In the general balance equation, which term is zero at steady state operation?
• Monel is composed primarily of which elements?
• The original meter was defined as 1/10,000,000 of the meridian through Paris between the North Pole and the Equator.
• What does an I/P transducer do?
• What is the stamen?
• In the film High School Musical, what is the name of the high school attended by the main characters?
• In cascade control, the primary loop controls the setpoint of which loop?
• In flammable liquid terminology, what does FP denote?
• Louis Pasteur is best known for his work in which field?
• The primary element in the mineral commonly called fool's gold is which element?
• In heat transfer contexts, the symbol h commonly denotes which quantity?
• The original definition of the meter was based on 1/10,000,000 of the meridian through which city between the North Pole and the Equator?
• Capillary action is best described as:
• Which chemical was released in the 1984 Bhopal disaster, causing thousands of casualties?
• What is the approximate molar ratio of nitrogen to oxygen in air used in combustion calculations?
• In a PID controller, what does integral mode accomplish?
• For a molecule to be considered organic, it must contain which element?
• Knudsen diffusion occurs when the pore diameter is smaller than the mean-free path of the gas molecules. In diffusion terminology, this is most significant when the diameter is smaller than which length?
• Anthelmintics are drugs used to treat which kind of infections?
• Which term describes the formal process of evaluating and authorizing changes to process technology to prevent new hazards?
• CSB stands for what organization?
• Deflagration refers to which type of explosion?
• According to Gibbs' Phase Rule, how many degrees of freedom does a pure liquid water system with one phase have?
• Which value equals the fourth root of 625?
• Which statement accurately describes slate formation?
• ERPG data are commonly used when developing evacuation strategies after the release of what?
• Which of the following lists all the US states that border Mexico?
• The Pythagorean theorem expresses a relationship between which elements of a right triangle?
• Is the view factor dimensionless?
• Christine Palmer is the name of Dr Strange's __________.
• Crater Lake National Park?
• Which Italian physicist invented the battery in 1800?
• What is the future value of $1 after 3 years at an annual interest rate of 100% with annual compounding?
• Dry air at STP contains approximately what mole percent of Argon?
• In an Eadie-Hofstee plot, which relationship holds between slope and intercept?
• HAZWOPER stands for Hazardous Waste Operations and Emergency Response. What is the primary focus of these guidelines?
• What is tritium?
• This process is used to separate components based on differences in their volatility.
• Which medication, derived from willow bark, was the first widely marketed as a tablet?
• In a first-order system's step response, what fraction of the final change is reached after one time constant?
• During the Diesel cycle, which process occurs at constant volume to reject heat?
• Which fundamental particle is neutrino?
• The boundary layer is the layer of fluid in immediate vicinity of a surface that has significant viscosity effects. Which option best describes it?
• Which heat transfer mode is described by the equation Q = hA(T∞ - Tw)?
• Which statement defines the Joule-Thomson coefficient?
• What term describes an inactive, dormant form of bacteria that enables survival under adverse conditions?
• In the isotope Cl-37, how many neutrons are present?
• How many Infinity Stones exist in the MCU?
• Mothballs are commonly made of paradichlorobenzene or which other chemical?
• The Fanning friction factor in pipe flow is a function of Reynolds number and relative roughness. Which option expresses this correctly?
• Piping and Instrumentation Diagram (P&ID) is a diagram that provides:
• Stokes flow is also known as creeping flow, with inertial forces small relative to viscous forces. Which term describes this flow?
• What is the exposure time for the TLV-STEL?
• The acronym NFPA stands for which organization?
• The dynamic behavior model abbreviated FOPDT stands for what?
• The eukaryotic cell structure involved in maintaining cell shape, enabling movement, and contraction is known as the:
• What is a detonation?
• The virial equation of state uses coefficients that account for molecular interactions. Which coefficients are used?
• What is the view factor (F12)?
• Which state is the smallest by land area?
• What is the active ingredient in Drano?
• In pharmacology, PRN is an abbreviation meaning what?
• Which device uses centrifugal force to separate solids from a gas stream?
• Which bacterium is the causative agent of bubonic plague?
• Which parameter describes the rate of exponential approach to the final value in a first-order system?
• Which equipment uses centrifugal force to separate solids from a gas stream?
• Octave Levenspiel is best known for contributions to which area of chemical engineering?
• According to the 2020 U.S. Census, which state experienced the largest percentage population decline from 2010 to 2020?
• What is a photoinitiator?
• Immobilized enzyme reactors are used in which context?
• What is the typical bond angle for sp2-hybridized carbon?
• The Nusselt number is defined as the ratio of convective to conductive heat transfer across a boundary.
• Isopropyl acetate contains which functional group?
• How many years are in a score?
• According to the material, how many fingers does God have in The Simpsons?
• The temperature at which water has its maximum density, used as a reference for specific gravity, is what?
• Cascade control is defined as ...
• What term describes a small circular DNA molecule that exists independently of the main bacterial chromosome and is often used in genetic engineering?
• Which organism was revived after approximately 46,000 years in Siberian permafrost?
• What is the Simpsons' street address?
• Which expression correctly represents the gas constant R in relation to Cp and Cv for ideal gases?
• In which city does 101 Dalmatians take place?
• Which statement best describes the Biot number?
• In popular culture, what does the expression Hakuna Matata mean?
• In The Simpsons Movie, the family relocates to which state?
• Erwin Schrödinger is best known for contributions to which theory?
• The Gram stain is used to classify cells based on differences in their ________.
• Which statement best describes an SN2 reaction?
• The flash point is defined as the lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture with air. Which of the following statements is true about the flash point?
• Which statement about Hawaii is true?
• Which NASA astronaut served as Mission Specialist on STS-129 and spent over 259 hours in space?
• Q = hA(T∞ - Tw) is named after which scientist?
• What is the price of a single coconut?
• Glyphosate is best described as which type of herbicide?
• Which term defines the maximum permissible exposure to a chemical averaged over a standard workday?
• The Frank R. Lautenberg Chemical Safety for the 21st Century Act updated which act enacted in 1976?
• Which statement best describes Christine S. Grant's AIChE role?
• Which statement about the Pitot tube is true?
• Which gas is commonly used to fill balloons?
• What is the molar volume of an ideal gas at STP in liters per mole?
• In chemical kinetics, zeroth order refers to a reaction rate that is:
• Which cellular structure is involved in maintaining cell shape, enabling movement, and contributing to contraction in eukaryotic cells?
• Roundup is the common name for which type of agricultural chemical?
• Humidity is best described as what in meteorology?
• Okazaki fragments are associated with which essential process?
• A small ring of DNA independent from the bacterium's main genome that can be taken in and expressed by bacteria is called a(n) __________.
• Which medication was developed by Bayer by modifying salicylic acid and became the first marketed in tablet form?
• Kg^-1 m^-2 s^4 A^2 is the base SI unit for which quantity?
• Equilibrium in thermodynamics is defined as which of the following?
• Saturation kinetics refers to the situation where the reaction rate:
• In fault tree analysis, which logic gate is used to represent that any one of several failures can cause the top event?
• What value is added to Fahrenheit to obtain Rankine (to three significant figures)?
• Which state is the leading producer of maple syrup in the United States?
• What is ARSST commonly used to evaluate?
• CHO cells are derived from the ovary of which organism?
• Acetone, Butanol and Ethanol refer to what in ABE fermentation?
• What is the Arrhenius equation?
• In the NFPA hazard diamond, which color represents specific hazards?
• Rust's formula can be represented as Fe2O3·xH2O. Which of the following resembles rust's formula?
• Vibranium is best known for being used in Captain America's shield and the Winter Soldier's arm.
• Hannibal Hamlin held which role during the Lincoln presidency?
• Rigor mortis is a condition at death in which
• 32.2 (lbf-ft/s^2) is equivalent to how many slugs?
• The Schmidt number is defined as the ratio of kinematic viscosity to the diffusivity.
• Which is the largest national park by area?
• Humidity is the measure of what in the atmosphere?
• The CGS unit of kinematic viscosity is named after which scientist?
• The Sherwood number is the dimensionless quantity that represents the ratio of which two types of mass transfer?
• What is the lowest point in the United States?
• Which rock is metamorphic and formed from shale?
• From which date does a typical utility patent term begin?
• Gilbert N. Lewis formulated which theory of acid-base reactions?
• Which statement correctly describes spark discharge?
• The Jungle was written by which author?
• Which country is home to the world's largest oil refinery producing about 1.24 million barrels per day?
• Which thermodynamic cycle consists of two isothermal and two isochoric processes?
• Location (City and State) of the 2024 AIChE Annual Student Conference?
• 2-hexene is best described as which type of compound?
• What is the typical bond angle between tetrahedral, sp3-hybridized carbon compounds?
• Which insect is known for eating its mate after mating?
• An azeotrope is a mixture that exhibits what behavior during boiling?
• In what year did the University of Manchester begin offering chemical engineering as a degree?
• Which of the following is a true fact about Death Valley?
• BLEVE stands for which of the following?
• The indefinite integral of sin(x) with respect to x equals which expression?
• Conduction in concentric spheres applies to which geometry?
• The Simpsons live in which city?
• On the NFPA hazard diamond, which color denotes reactivity hazards?
• In Michaelis-Menten kinetics, Km is defined as
• The Mach number is defined as the ratio of the fluid velocity to the speed of sound in the medium.
• Buoyancy force on a submerged object is directed which way?
• Hess's law states that the enthalpy change of a chemical process is independent of the path taken.
• The F is for friends line is part of which song from a popular animated series?
• In an elementary rate law, the reaction orders are identical to the stoichiometric coefficients. This implies what about the rate law?
• Layer of Protection Analysis is used to assess what?
• What describes a compressed gas?
• Which statement is true regarding applying the Fenske equation to determine minimum theoretical plates?
• How many acres are in a square mile?
• Which metallic element is typically extracted using the Kroll Process?
• An elementary rate law is followed when the reaction orders are identical to which quantities?
• A Mollier diagram is another name for which thermodynamic diagram?
• Who first proposed the heat conduction equation in 1822?
• The first university to offer chemical engineering as a degree starting in 1887.
• Which statement best describes an oxidizer?
• Before Pedro Castillo became president, what was his primary profession?
• In control theory, a transfer function is defined as:
• Grey's Anatomy is set in which city?
• Which gas was used to provide buoyancy in the Hindenburg airship?
• Adsorption refers to which phenomenon?
• Which type of nucleic acid does SARS-CoV-2 use as its genetic material?
• Differentiation yields what geometric interpretation in a function's graph?
• Which dimensionless number compares momentum diffusion to thermal diffusion?
• What is the premise of the show Cyber Chase?
• Which compound was added to Grand Rapids tap water in 1945 to reduce tooth decay in children?
• In Michaelis-Menten kinetics, at saturating substrate concentrations, the reaction rate approaches
• Which of the following best describes an explosive?
• What is the value of 4 factorial?
• Maxwell's equations predict the existence of which phenomenon?
• Jamestown is known for which historical fact?
• What is the equator?
• The acronym ARSST stands for:
• Which statement best describes an action potential?
• Sphericity is defined as the measure of how close an irregularly shaped object is to which shape?
• A dialysis machine is an example of which type of separation?
• Which list correctly identifies the five sides of the dust explosion pentagon?
• What is the primary use of an Eadie-Hofstee plot in enzyme kinetics?
• Who is Maude Flanders?
• Which term describes the tightness on the surface of a liquid caused by molecular cohesion?
• Hooke's Law states that the force needed to extend or compress a spring by a given distance is proportional to which quantity?
• What is a fermenter?
• Which equipment uses centrifugal force to separate solids from a gas stream?
• What is the name of the control valve type that is a 3-way solenoid valve?
• Which statement about the Lautenberg Act is true?
• Smallpox vaccine, the world's first vaccine, was developed by Edward Jenner in 1796 to protect against which disease?
• Which statement about azeotropes is true?
• An azeotrope is defined as a mixture that boils to vapor with what property?
• A barn is a unit of area used to express cross-sectional area of nuclei and equals which value?
• The view factor F12 is used in which mode of heat transfer?
• ERPG data are commonly used to support which activity?
• Under which condition is the lumped solution (uniform temperature throughout the body during transient heat transfer) assumed valid?
• Which of the following defines the ISE performance criterion?
• Who is Fibonacci?
• Which dimensionless number is the ratio of the kinematic viscosity to the thermal diffusivity?
• What does the Flory-Fox equation express for polymers?
• Isopropyl acetate is best described as which type of compound?
• The boundary layer near a solid surface arises primarily due to which fluid property?
• 101 Dalmatians is set in which city?
• Which state has the largest number of endangered species?
• What is the net number of ATP molecules produced in glycolysis from one glucose molecule?
• Which Infinity Stone requires a sacrifice to obtain?
• The sudden closing of a valve leads to which undesirable phenomenon?
• The 0 to 4 range on the NFPA hazard diamond represents
• What is the most common type of electrostatic discharge in industry?
• Which artificial sweetener has been classified by the World Health Organization as possibly carcinogenic to humans?
• Lyme disease is caused by which bacterium transmitted to humans through tick bites?
• On a P&ID, what does TIC indicate?
• Which are the three types of RNA used in protein synthesis?
• The 2016 update of the 1976 Toxic Substances Control Act (TSCA) was named after which former New Jersey Senator?
• In liquid-liquid extraction, the phase containing the dissolved solute in the extracting solvent is called the extract phase.
• Erwin Schrödinger won a Nobel Prize for contributions to which field of physics?
• Feedforward control is a control strategy that:
• Who is Rihanna?
• Which field most commonly uses the van Deemter plot to evaluate column efficiency?
• On STS-129, how many spacewalks did Robert L. Satcher Jr. participate in?
• Which gas is the third most abundant by volume in dry air?
• Sacagawea acted as translator during the exploration of which territory?
• In a Pitot tube, the velocity of the fluid is determined by relating stagnation pressure to static pressure through which principle?
• What is the primary function of xylem vessels in vascular plants?
• Saccharomyces cerevisiae is the most used species of yeast in commercial ethanol production. In which industrial context is it most commonly employed as a yeast species?
• Hannibal Hamlin served as Lincoln's vice president during which years?
• Which pair of Georgia senators were elected resulting in a 50-50 Senate?
• In the explosive behavior model, the volume is raised to which power?
• How many companies formed the DIERS consortium in 1976?
• Space time τ is defined as the volume divided by volumetric flow rate. Which statement is true about τ?
• Which equation of state is commonly used to model non-ideal gas behavior in hydrocarbon mixtures?
• Amagat's Law states that the volume of a gas mixture is the sum of the pure component volumes. Which statement best reflects this?
• The reciprocal of x is which expression?
• Which statement about radiocarbon dating using C-14 is true?
• Which organization publishes guidelines for emergency relief system design in chemical processing facilities?
• Chromium is added to stainless steels to significantly increase which property?
• Who discovered oxygen in 1774?
• Clara Barton is historically associated with founding which organization?
• The Risk Management Plan (RMP) implements Section 112(r) of which federal legislation?
• Which term describes a plant that produces naked seeds?
• What is a disturbance variable?
• Lepidopterophobia is a fear of which group?
• Lexus is the luxury vehicle division of which automaker?
• The first name of Mr. Krabs, owner of the Krusty Krab, is:
• In Sleeping Beauty, which name does Princess Aurora use to conceal her identity?
• Anthrax-causing bacteria belong to which genus?
• Which formula gives the future value after n years with annual compounding at rate r?
• Who is the main antagonist in The Princess and the Frog, also known as the Shadow Man?
• Which leader’s tenure at GE saw the market value rise from $12 billion to $410 billion?
• Who is associated with chemical safety in industrial practice?
• The 1984 Bhopal disaster involved the release of a toxic gas at a pesticide plant in which country?
• What does the van Deemter plot illustrate?
• Yellowstone National Park?
• Gravitational waves in recent observations were produced by the merger of which astronomical objects?
• Which elements exist as liquids at standard temperature and pressure?
• Which dimensionless number is defined as the ratio of kinematic viscosity to diffusivity?
• Tesla is best known as which of the following?
• The Wittig reaction forms alkenes from aldehydes or ketones using what reagent?
• The stiffness of water on a frozen lake is primarily due to which property?
• What best describes insulin?
• The Damköhler number compares the rate of reaction to the rate of convective transport. Which of the following statements is true?
• The Damköhler Number is defined as the ratio of which quantities, evaluated at the entrance?
• Louis Pasteur is renowned for his work in fermentation. Which field does this most closely relate to?
• Alpha particles are a byproduct of nuclear decay that cannot pass through the skin.
• Which type of image is always seen in a plane mirror?
• What does the 'D' in COVID-19 stand for?
• The heat conduction equation is a foundational relation in which field?
• Which scientist is associated with fermentation and wine spoilage and is widely credited with founding modern microbiology?
• Where was Mike Ehrmantraut working when Saul Goodman first meets him?
• A Hartmann Tube is used to investigate which explosions?
• Which statement reflects Boyle's Law?
• Archimedes' Principle states that the weight of the fluid displaced by an object is equal to the buoyant force.
• In a multivariable control context, a decoupler primarily serves to:
• Retroviruses are equipped with which enzyme that allows DNA to be transcribed from an RNA template?
• What does IChemE stand for?
• In a distillation system, what is the reflux drum used for?
• In fault tree analysis, which logic functions are used to evaluate risks in a process?
• Which branch of thermodynamics applies microscopic analysis based on probability to evaluate macroscopic properties?
• Pedro Castillo is the president of which country?
• C-14 is an isotope commonly used for dating which types of artifacts?
• Monel refers to which type of material?
• Planck's Law expresses the spectral radiance of a black body as a function of which variables?
• What legal principle prohibits trying a person twice for the same offense?
• Complex poles in a transfer function lead to which type of behavior?
• What are the four major phases of a cell growth curve?
• In what year did the East Palestine train derailment occur?
• The thin lens equation relates object distance, image distance, and focal length. Which form is correct?
• Which equation expresses the Pythagorean Theorem for a right triangle with legs a and b and hypotenuse c?
• Which statement about benzene is correct?
• In an inelastic collision, which statement is true?
• What does the compressibility factor Z quantify in gas behavior?
• Two bits in U.S. currency equal how many cents?
• Fermentation is best described as which type of process?
• What is slate?
• The release and ignition of which chemical were linked to the Flixborough disaster in June 1974?
• For an ideal gas, Cp minus Cv equals which constant?
• In gas treatment, what is the unit operation that uses countercurrent gas and liquid flow to remove soluble components?
• Who proposed the rate equation for convective heat transfer in 1701?
• The Helmholtz Free Energy (A) is the Legendre transform of which energy with temperature replacing entropy as the independent variable?
• Which dimensionless number is defined as the ratio of convective mass transfer to diffusive mass transfer?
• What is the chemical formula for ethanol?
• According to Amagat's Law, the volume of a gas mixture is the sum of what?
• In an endothermic reaction, the standard enthalpy change ΔH° is positive.
• Walter White is a central character in which TV series?
• In linear algebra, what is an eigenvalue?
• The Prandtl number is defined as the ratio of thermal diffusivity to momentum diffusivity.
• What is the respiratory quotient (RQ)?
• In which law is the diffusion coefficient DAB used to relate flux to concentration gradient?
• What is the bond angle between the two O–H bonds in a water molecule?
• Who was AIChE president in 2021?
• What is a barn in nuclear physics?
• Who published the law of induction in 1831?
• The 2024 AIChE president (current president elect)?
• In a PID controller, which term is primarily responsible for eliminating steady-state offset?
• What is the primary function of a turbine in fluid systems?
• What does the definite integral notation ∫_0^4 f(x) dx represent?
• A fathom is defined as how many feet?
• In Michaelis-Menten kinetics, Km is defined as what?
• On the NFPA hazard diamond, which color denotes health hazards?
• What is the structure formed from an ovule after fertilization in seed plants?
• What does the Fenske equation calculate in distillation design?
• TSCA stands for Toxic Substances Control Act.
• Which statement correctly describes the James Webb Space Telescope?
• Chemiluminescence is defined as
• What is a CSTR?
• Which statement about a cold front is correct?
• The scientist associated with radiation and pioneering work on radioactivity is:
• Which statement about Christine S. Grant's AIChE presidency is true for 2022?
• Hund's rule is used to determine the ground state of which system?
• What is the main mission of NIOSH as described?
• What is the volume, in liters, of one mole of an ideal gas at STP?
• In refining energy considerations, distillation is typically responsible for what fraction of total energy?
• Which state was the fastest growing by percentage between 2010 and 2020 according to the 2020 Census?
• The exponent 0.8 in the h-Re relationship is characteristic of which flow regime in pipes?
• The Levenspiel plot is a graphical method used to analyze reactor performance for which type of reactors?
• The Lautenberg Chemical Safety for the 21st Century Act updates which federal law?
• 5.08 centimeters is equal to how many inches (to three significant figures)?
• Which uranium isotope is fissile and used as fuel in nuclear reactions?
• In The Little Mermaid, which character sings "Kiss the Girl"?
• What is a thiol?
• Sherwood Number represents the ratio of what?
• Which dimensionless number measures the ratio of inertial to gravitational forces?
• How many legs do insects typically have?
• N-linked glycans are attached to which amino acid in naturally occurring glycoproteins?
• Flame arresters function by which mechanism?
• Which statement about insulin reflects its regulatory milestone?
• What is a quark?
• How many kittens does Duchess have in The Aristocats?
• TLV-STEL stands for which concept?
• Which of the following temperatures is used as the reference for water density when calculating specific gravity?
• Which gas is the fourth most abundant by volume in dry air?
• Which pathway is the primary carbon dioxide fixation pathway in photoautotrophs and chemolithotrophs?
• Which statement describes a recycle stream in process engineering terms?
• The NFPA flammability rating is based on the value of which parameter?
• What is a beta particle?
• Which statement best defines oxidation?
• The SI unit Newton is named after which scientist?
• The specific gravity of a liquid or solid is based on the density of water at this temperature.
• Which individual served as AIChE president in 2021?
• The Sherwood Number is defined as what?
• Amagat's Law states which of the following?
• In vapor–liquid equilibrium for a dilute solute, Henry's Law relates the total pressure P, the vapor-phase mole fraction y_A, the liquid-phase mole fraction x_A, and the temperature-dependent Henry's constant H_A(T) by which equation?
• What does PCR stand for in molecular biology?
• What is the chemical name for baking soda?
• Which agency administers workplace safety and health standards in the United States?
• Heck reaction is a palladium-catalyzed cross-coupling that forms what from aryl or vinyl halides and alkenes?
• Which of the following shows the bond angle between the two O–H bonds in water as approximately 104.5 degrees?
• In The Simpsons, what is the Treehouse of Horror?
• Borax is the common name for which chemical?
• Which line is recognized as Homer's high school yearbook quote?
• Which parameter quantifies the rate of oxygen transfer from gas to liquid per unit volume in bioprocessing?
• What is Ohm's Law?
• What are the two options for packing a column?
• Who introduced the concept of electrical resistance in 1827?
• What does Kirchhoff's (junction) rule state?
• Which type of enzyme inhibition occurs when an inhibitor binds only to the enzyme-substrate complex?
• Malaria is caused by which parasite?
• In steady-state operation, the accumulation term in the general balance equation is what?
• Which state is the largest producer of maple syrup?
• Which dimensionless number measures the ratio of inertial to gravitational forces?
• Which statement best defines acute toxicity?
• What is the value of (625)^(1/4)?
• Which dimensionless number defines the ratio of convective to conductive heat transfer across a boundary?
• Mixing household bleach with which kitchen compound produces toxic chlorine gas?
• Which statement correctly identifies e?
• What is the triple point in thermodynamics?
• Space time (τ) is defined as which of the following?
• According to the third law of thermodynamics, entropy is zero for which condition?
• Maxwell's Equations describe the behavior of which physical quantities?
• Before becoming Saul Goodman, which name did the character James McGill use?
• Iron pyrite has which chemical formula?
• Pain and Panic are characters associated with which Disney villain?
• Equimolar counterdiffusion is characterized by which molar flux relation?
• Which term refers to a formal process for evaluating and authorizing changes to a process to prevent new hazards?
• What is an I/P converter?
• Which statement about compressed gases is correct?
• A Levenspiel plot is used to determine which aspect of reactor design?
• Velma Dinkley is a character from which franchise?
• Which statement about monoclonal antibodies is accurate?
• The overpressure from explosions is commonly estimated by using an equivalent mass of which substance?
• What are the SI units for thermal conductivity?
• The view factor F12 is best described as which of the following?
• A Hartmann Tube is used to investigate which type of explosion?
• Select the correct chemical formula for ethanol.
• Adsorption is used in separation processes because molecules what?
• IDLH is the acronym for which safety term?
• What is a plug flow reactor?