Chemical equilibrium is a concept introduced in the first semester of chemistry. However, students usually just look at equilibrium as a number to a solution and do not actually understand what is occurring at the molecular level. These questions will hopefully probe these usually overlooked concepts.
1. What does it mean for a system to be at equilibrium?
2. What are the compounds doing if a system is at equilibrium?
3. What factors influence the equilibrium?
4. Does temperature change the equilibrium? Why or why not?
5. What is the relationship between equilibrium and how fast the reaction occurs?
6. Assume we have 15 A molecules and A is in equilibrium with B. The equilibrium constant is 1.5. How many B molecules do we have?
7. What would happen if we then added 6 B molecules?
Very true. Equilibrium is a very difficult concept for students to understand at the molecular level. I think your first four questions strike the right balance between being open-ended yet focused enough to direct the student's attention to a reasonable number of ideas. I'm not sure about how useful the last two questions will be, as they might cause students to switch from conceptual understanding to more algorithmic thinking. Overall, though, I think this is a good start.
ReplyDeleteGood set of questions that approach a topic that can be a challenge to many students. I think the first 5 questions are broad enough to get a good feel for the students understanding and ideas about the concept of equilibrium, while at the same time not restricting the student to a specific line of thought. I like the 2 scenario questions at the end from the point of making the students apply their knowledge to a realistic scenario, however I'm not sure if the students will get hung up trying to do math, and not necessarily using their understanding of "equilibrium" to answer the questions. Interested to hear the responses.
ReplyDeleteWhat a good fundamental topic in chemistry and biochemistry to probe! I do agree with the above comments concerning the first 5 questions. But, I also understand why you do have the last 2 in your question set. I think the last 2 would give you a good picture in real life situations too. A student who is able to solve these question not only demonstrate to you that they understand what equilibrium is and what factors affect it, but also shows they can manipulate a reaction to favor what end product they want. Good questions, I think
ReplyDeleteI agree with Erika; I find very useful the first five questions. For the last two questions to take place you may need a little bit more introduction to get started (as a guide for the student to carry her/him throughout the interview).
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