Calculating the molarity when mixing two different solutions

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    Mixing Molarity
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Discussion Overview

The discussion revolves around calculating the molarity when mixing two different solutions, specifically 45 mL of 0.1174M K2SO4 and 35 mL of 0.2504M HNO3. Participants explore whether a reaction occurs and how to account for the stoichiometry in their calculations.

Discussion Character

  • Homework-related
  • Debate/contested

Main Points Raised

  • One participant outlines a method for calculating the total moles of K2SO4 and HNO3, suggesting that the balanced equation indicates the need to multiply the moles of HNO3 by 2 due to the stoichiometric coefficient.
  • Another participant questions whether the problem statement is complete and suggests that the task may involve finding the molarity of each ion rather than the overall molarity of the solution.
  • A later reply expresses uncertainty about whether it is valid to calculate the molarity of the final solution when mixing two different solutions, proposing that only ion concentrations may be determined instead.
  • Some participants agree that it may not make sense to assign a single molarity to a mixture of solutions, reflecting on the implications of mixing solutions of different concentrations.

Areas of Agreement / Disagreement

Participants express uncertainty about the correct approach to the problem, with some agreeing that calculating a single molarity for the mixture may not be appropriate. Multiple competing views remain regarding the interpretation of the problem and the calculations involved.

Contextual Notes

Participants note the potential confusion surrounding the mixing of solutions and the implications of stoichiometry in determining concentrations. There is a lack of clarity on whether a reaction occurs and how that affects the calculations.

AMan24
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Homework Statement


You mix 45-mL of 0.1174M K2SO4 and 35-mL of 0.2504M HNO3

Homework Equations


none.

The Attempt at a Solution



So I'm supposed to find the number of moles of the K2SO4 and add it to the number of moles of 0.2504, then add the two volumes, and divide the total number of moles by the total volume.

My question is, if i write a balanced equation, i get K2SO4 + 2HNO3 = 2KNO3 + H2SO4, does that mean for the number of moles of HNO3, before i add it to the number of moles of K2SO4 i have to multiply the number of moles of HNO3 by 2, because of the coefficient.

I could also be doing this problem entirely wrong by assuming a reaction is occurring and even needing to balance. There is nothing in my book talking about reactions when mixing two different solutions.
 
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That's the complete problem statement?
 
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Bystander said:
That's the complete problem statement?

In this case the problem said to find the molarity of each ion present in the solution formed. But i can already do that, and on my test tomorrow there's going to be a question that has a part a) and b) (professor told us) and its going to ask for the ion concentration and the molarity of final solution.

Now you got me thinking that it isn't possible to do what I'm doing when given two different solutions, and that you can only find the ion concentration when mixing two different solutions, not the molarity. Is this true? If that's true then my professor might have meant mixing two same solutions of different molarity.
 
AMan24 said:
might have meant mixing two same solutions of different molarity
That would be my take on it.
 
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Bystander said:
That would be my take on it.

yeah you're definitely right, i just realized how it doesn't even make sense to have one molarity for a mixture of solutions
 

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