Critical Thinking Questions

1. What is the purpose, goal, or point?

2. What is the problem or issue being solved or described?

3. On what data or evidence is the decision / definition / problem based?

4. What inferences are being made from what kind of data, and are these inferences

legitimate?

5. What is the solution, outcome, or resolution of the problem or issue?

6. What are the short-term and long-term implications of the solution / consquences

of the outcome?

7. What are the biases or assumptions behind the inferences, selection or collection

of data, or framing of the problem / experiment?

8. What are the basic concepts or terms being used? How do these definitions affect

the framing / understanding of the problem?

9. What point of view is being expressed? What political / ideological / paradigmatic

considerations inform or govern or limit point of view?

10. How would someone from a related but different discipline look at the problem /

solution / issue, and could an interdisciplinary approach improve the analysis /

discussion / evaluation?

(1) What specifically is the product?

While this question could be a CTQ from the clarification category, it is not a good critical thinking question because it is superficial and the information is about the product and is not relevant to solving for the conversion and reactor volumes as well as critiquing the answers.

(2) Is the reactor really tubular or does it have some bulges in it?

This is not a good critical thinking question because we know in Chapter 1 that even if the reactor varies in cross sectional area the conversion-volume relationship is the same.

(3) Other no so good critical thinking questions

Will this be on the exam?

What’s the correct answers?

Why is there a “2” in this equation?

What are the units of this symbol?

While the last two questions are not CTQs, they may be valid questions.

(4) Is the rate law expected to hold at a lower temperature?

This question is not a good CTQ because it is superficial and not sufficiently penetrating.

Better would be

Under what conditions might the activation energy and reaction order change in temperature. This question is a good CTQ because it explores the assumptions under which the rat e law might change, such as in Langmuir Hinschelwood kinetics.

(5) What equations should I use to solve the problem?

This question is not a good CTQ.

A similar, but better question is,

What thought process led you to choose the CSTR equation for the case of constant volumetric flow rates?

This question asks to describe the assumptions needed to arrive at the CSTR equation.

(6) Do the experimental data taken to formulate the rate law justify the reaction order being in integer?

This is a good CTQ because it probes the reason of perhaps rounding a reaction order of 1.8 up to a second order reaction when the evidence from the data support an order of 1.8.

(7) What are the consequences of make the reaction order in integer?

This is a good CTQ because it probes implications and consequences.

(8) The liquid phase volumetric flow rate was et at 25 dm3/s giving as space time of 45 seconds. This flow rate is quite high. Do you feel this flow rate can be achieved in practice and that 90% conversion can be achieved?

This is a good CTQ because it challenges the questions perspective and view points from a practical standpoint (is ) reasonable, and probes implications as to whether 90% conversion can be achieved because of perhaps poor mixing resulting from the high flow rates.

(9) Constant molar flow rates were assumed in the treatment of this question, how would your approach to this problem differ if this assumption were not valid? Assuming that the given reaction is highly exothermic, what is the advantage of using a semi-batch reactor for this process?

These questions are of the Socratic form because they probes implications and consequences of changing the conditions of the original problem. The student is required to understand the problem in its entirety rather than just memorizing the approach used for specific conditions.