Trick Question? (Making a solution)

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In summary, the conversation discusses a student's attempt to make a 0.5 M KNO3 solution at 12 degrees C and whether this is possible. The student also asks about the relationship between temperature and molarity, and how to calculate the solubility constant of KNO3 without knowing the concentrations. Suggestions are made to check the solubility constant in a reference source and to calculate the Ksp using the given molarity of 0.5. The conversation ends with the student expressing gratitude for the advice and multiple perspectives on the problem.
  • #1
needphyshelp
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Homework Statement


A student wishes to make a 0.5 M KNO3 solution at 12 degrees C. Is this possible? Explain, and show calculations to support your answer.
[This is a question related to a solubility lab]


Homework Equations


In my experiment, I saw that as temperature decreased and as volume increased, molarity decreased, but I don't know if temperature is actually related to this observation.


The Attempt at a Solution


.5 M solution = .5 moles KNO3/1L, right?
Does temperature affect this?
 
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  • #2
Temperature effects any ability to make any kind of solution, mainly because reactions slow down with a decrease in temperature.

As for molarity, bond forming and other reactions take longer to occur because of the cold. You might want to look up the freezing point of KNO3 if possible.

And to answer your question, yes. a 0.5 M solution of KNO3 means 0.5 moles per 1 L soln.
 
  • #3
needphyshelp said:

Homework Statement


A student wishes to make a 0.5 M KNO3 solution at 12 degrees C. Is this possible? Explain, and show calculations to support your answer.
[This is a question related to a solubility lab]


Homework Equations


In my experiment, I saw that as temperature decreased and as volume increased, molarity decreased, but I don't know if temperature is actually related to this observation.


The Attempt at a Solution


.5 M solution = .5 moles KNO3/1L, right?
Does temperature affect this?

What's the solubility constant of KNO3 AT 12 degrees C?
 
  • #4
How can I calculate Ksp without having the concentrations? I know Ksp = [K+][NO3-]... would I just plug in .5 to get Ksp and go from there?
 
  • #5
needphyshelp said:
How can I calculate Ksp without having the concentrations? I know Ksp = [K+][NO3-]... would I just plug in .5 to get Ksp and go from there?

I would think so; you have 0.5mol of KNO3 assuming 1L of solution, so that means you have 0.5mol [K+] and 0.5mol [NO3-]. This would give you a Ksp of 0.25, but then again it's been a while since I've done this.
 
  • #6
This is pretty well soluble salt, so it will not have Kso listed. However, if you will check CRC handbook or some other, similar source, you should be able to find what is KNO3 solubility in grams per 100 g of water - check, if it is not less then 0.5M.
 
  • #7
Thank you all so much for your input - I now have a few different ways to look at this problem. I really appreciate it!
 

What is a "trick question" in the context of making a solution?

A trick question in this context refers to a question that is intentionally misleading or confusing in order to test a person's knowledge or critical thinking skills.

Why is it important to be aware of trick questions when making a solution?

Being aware of trick questions can help ensure that the solution being created is based on accurate information and not on false assumptions or misunderstandings.

How can one identify a trick question when making a solution?

One way to identify a trick question is to carefully read and analyze the question, looking for any inconsistencies or logical fallacies. It is also helpful to ask for clarification or additional information if needed.

What are some common types of trick questions when making a solution?

Some common types of trick questions in this context include those that contain double negatives, those that use vague or ambiguous language, and those that make assumptions or present false information as fact.

How can one avoid falling for a trick question when making a solution?

To avoid falling for a trick question, it is important to carefully read and analyze the question, and to verify the information before making any conclusions. It can also be helpful to take a step back and approach the question from a different angle or perspective.

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