Quick Question about a Concentration Problem

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Discussion Overview

The discussion revolves around a concentration problem related to the dissociation of various compounds in solution. Participants explore the implications of different solubility and dissociation behaviors of compounds, particularly focusing on calcium chloride, sodium nitrate, barium sulfate, and acetic acid. The conversation includes elements of homework assistance and conceptual clarification regarding ion concentration and dissociation reactions.

Discussion Character

  • Homework-related
  • Conceptual clarification
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that the answer to the concentration problem is 6E, reasoning that more moles lead to higher ion concentration.
  • Another participant points out that methanol does not dissociate, while acetic acid only partially dissociates in water, and barium sulfate is not soluble.
  • A participant emphasizes that at 1 mol/L, calcium chloride and sodium nitrate are fully soluble, while barium sulfate is not, and discusses the importance of writing dissociation equations.
  • There is a correction regarding the nature of acetic acid, clarifying it is a weak acid that dissociates only partially.
  • One participant questions the number of ions produced by calcium chloride, leading to a discussion about the dissociation of chloride ions.
  • Another participant confirms that calcium chloride produces three ions in solution and clarifies the misunderstanding regarding chloride dissociation.
  • There is a request for clarification on how acetic acid dissociates, indicating uncertainty about the concept of equilibrium reactions.

Areas of Agreement / Disagreement

Participants express differing views on the dissociation behaviors of the compounds discussed, particularly regarding acetic acid and the interpretation of ion counts. The discussion remains unresolved with multiple competing perspectives on the concentration problem.

Contextual Notes

Some participants exhibit uncertainty about the dissociation of acetic acid and the concept of equilibrium, indicating potential gaps in understanding. There are also corrections made to earlier statements, reflecting the evolving nature of the discussion.

Lori

Homework Statement



upload_2017-11-20_21-41-11.png

Homework Equations


M = n/1 L

The Attempt at a Solution


I was wondering if the answer is 6E. I'm not too sure about what the question is asking but i do know that the more moles there are, the more concetration of ions there will be. So, E seems like the answer since it has more atoms in the compounds. Is my logic correct?[/B]
 

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Hi,

Practically, (in P=atmospheric and T=25°C) the dissociations that you need to take into consideration (compare) are B and C. Methanol (D) does not dissociate and acetic acid (E) dissociates only partially in water. Finally, BaSO4 (A) is not soluble in water.
 
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No need for Ksp here. At 1 mol/L you can safely assume both CaCl2 and NaNO3 to be fully soluble and BaSO4 to be not soluble at all. Then, it is just a matter of number of ions produced during dissociation (writing the dissociation reaction equation will help if you don't see it immediately).

CH3COOH is acetic acid (not an alcohol!). It definitely dissociates, but as it is a weak acid, only partially. Safe to assume no more than just few % will be dissociated (actually just a few tenths of a %).
 
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Sorry, my bad, of course acetic acid is not an alcohol.

Post #2 has been edited in order to be correct.
 
Borek said:
No need for Ksp here. At 1 mol/L you can safely assume both CaCl2 and NaNO3 to be fully soluble and BaSO4 to be not soluble at all. Then, it is just a matter of number of ions produced during dissociation (writing the dissociation reaction equation will help if you don't see it immediately).

CH3COOH is acetic acid (not an alcohol!). It definitely dissociates, but as it is a weak acid, only partially. Safe to assume no more than just few % will be dissociated (actually just a few tenths of a %).
If I were to count the ions for CaCl2 would be be 3 ions? Because Cl disocciates into 2 ions
 
Lori said:
If I were to count the ions for CaCl2 would be be 3 ions? Because Cl disocciates into 2 ions

Three ions, yes. Not sure what you mean by "Cl dissociates into two ions". There ARE two moles of Cl- ions per each CaCl2 mole, there is no "Cl" (nor "Cl2" for that matter) that can dissociate.
 
Borek said:
Three ions, yes. Not sure what you mean by "Cl dissociates into two ions". There ARE two moles of Cl- ions per each CaCl2 mole, there is no "Cl" (nor "Cl2" for that matter) that can dissociate.
Oh. How would the acetic acid work. i could the ions
 
Lori said:
Oh. How would the acetic acid work. i could the ions

English please.

Acetic acid dissociates according to the equation

CH3COOH ↔ CH3COO- + H+

but it dissociates only partially (it is an equilibrium reaction, judging from your other questions something you have probably not yet heard about).
 

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