A gaseous reactant is fed into a 3-liter mixed reactor at 1 liter/second, yielding a space time of ______________ seconds?
Show answer Hide answer
Answer: B. 3
Explanation
Space time is defined mathematically as the reactor volume divided by the volumetric feed rate. Dividing three liters of reactor volume by one liter per second yields three seconds. This fundamental parameter measures the time needed to process one reactor volume of feed. Space time is the inverse of space velocity in continuous flow reactor engineering design. Reference conditions for volumetric feed rates must be specified for accurate scale-up calculations. Flow reactor performance equations utilize space time to integrate reaction kinetics effectively.
Continuous industrial reactors are sized using space time to ensure adequate reactant conversion. Residence time distributions relate closely to space time in well-mixed continuous flow systems. Plant operators monitor volumetric feed rates and reactor volumes to maintain desired space times. A space time of one second would correspond to much smaller reactor volumes or higher flow rates. Options C and D represent incorrect mathematical inversions or erroneous arithmetic calculations. Simple division of volume by volumetric flow rate gives exactly three seconds.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. For a first-order reaction A → B within a spherical porous catalyst pellet where center concentration is much lower than surface concentration, the process is limited by__________________?
Show answer Hide answer
Answer: A. Diffusion within the pellet
Significant concentration gradients between the pellet surface and center indicate slow internal diffusion. When reactant molecules cannot diffuse rapidly through pores, the core remains starved of reactant. Internal por...
Q2. A first-order irreversible reaction A → B is conducted for a set duration in both constant-volume and variable-volume reactors, implying that _____________ in the two setups?
Show answer Hide answer
Answer: B. Conversion in both will be the same but concentrations will be different
First-order reaction conversions depend exclusively on space time and the reaction rate constant. Because rate expressions for first-order systems simplify, volume changes do not alter conversion calculations. Reactant c...
Q3. A chemical reaction catalyst _______________ the Gibbs free energy change of the reaction?
Show answer Hide answer
Answer: C. Either A. or B.; depends on the type of catalyst
Catalysts alter the reaction pathway to lower activation energy but do not change the overall thermodynamic Gibbs free energy change of the reaction.
Q4. The consecutive first-order reaction sequence X → Y → Z is conducted in a CSTR. Which respective curves illustrate the concentration profiles of X, Y, and time-dependent Z ?
Show answer Hide answer
Answer: B. III, II, I
Reactant X is consumed continuously, resulting in a monotonically decreasing concentration profile over time. Intermediate Y is formed from X and consumed to form Z, causing its concentration to peak. Product Z accumulat...
Q5. Which of the following materials is not classified as an elastomer ?
Show answer Hide answer
Answer: D. None of these
Polyisoprene is a natural or synthetic polymer possessing characteristic rubbery elastomeric properties. Neoprene is a synthetic chloroprene elastomer widely valued for chemical and weather resistance. Nitrile-butadiene...
Q6. A chemical reaction takes place when the energy of the reactant molecules matches or exceeds __________________ the reaction activation energy?
Show answer Hide answer
Answer: D. Equal to or more than
Reactant molecules must collide with kinetic energy meeting or exceeding the activation energy barrier. Activation energy represents the minimum energy requirement for chemical bonds to break and reform. Successful molec...