Chemical Reaction Engineering Questions and Answers – Space Time and Space Velocity


This set of Chemical Reaction Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Space Time and Space Velocity”.

1. Space time is defined as ____
a) Time required to process unit volume of feed
b) Time required for the reaction to occur
c) Time required to produce unit volume of product
d) Time to process the entire volume of feed entering
View Answer

Answer: a
Explanation: Space time is the time spent by a unit volume of reactants inside the reactor. It is the performance measure for a flow reactor.

2. The unit of space velocity is ____
a) sec
b) sec-1
c) m3
d) m-3
View Answer

Answer: b
Explanation: Space velocity has the dimensions of time-1. A space velocity of 2 hr-1 implies that 2 reactor volumes are fed per hour.

3. Space time as a function of molar feed rate and initial concentration is given as ____
a) \(\frac{VC_{A0}}{F_{A0}} \)
b) \(\frac{C_{A0}}{VF_{A0}} \)
c) \(\frac{VF_{A0}}{C_{A0}} \)
d) \(\frac{C_{A0}}{F_{A0}} \)
View Answer

Answer: a
Explanation: Space time is the ratio of the product of reactor volume and initial concentration to the feed rate. \(\frac{VC_{A0}}{F_{A0}} \) has the same unit as that of space time.

4. If V represents volume and Q represents volumetric flow rate, then which of the following is a valid expression for space velocity?
a) \(\frac{V}{Q} \)
b) \(\frac{Q}{V} \)
c) Q × V
d) \(\frac{V}{C_{A0}} \)
View Answer

Answer: b
Explanation: Space velocity is the ratio of volumetric flow rate to volume. It has the unit hr-1.

5. State true or false.
Space velocity is the number of unit volumes of feed that can be treated per unit time.
a) True
b) False
View Answer

Answer: a
Explanation: Space velocity is the inverse of space time. It gives a measure of what volume of feed can be processed in a unit time.

Sanfoundry Global Education & Learning Series – Chemical Reaction Engineering.

To practice all areas of Chemical Reaction Engineering, here is complete set of 1000+ Multiple Choice Questions and Answers.



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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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