Quick Question about a Concentration Problem

In summary, the conversation discusses the dissociation of various compounds and the number of ions produced during dissociation. The main focus is on determining the number of ions for CaCl2 and acetic acid, both of which dissociate partially. It is mentioned that BaSO4 is not soluble in water. The conversation also clarifies that acetic acid is not an alcohol and that Cl ions do not dissociate into two ions.
  • #1
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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  • #2
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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  • #3
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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  • #4
Sorry, my bad, of course acetic acid is not an alcohol.

Post #2 has been edited in order to be correct.
 
  • #5
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
 
  • #6
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.
 
  • #7
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
 
  • #8
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).
 

1. What is a concentration problem?

A concentration problem involves finding the amount or proportion of a substance in a solution or mixture.

2. How do you calculate concentration?

Concentration can be calculated by dividing the amount of solute (substance being dissolved) by the total volume of the solution.

3. What are the units of concentration?

The units of concentration depend on the type of solution being measured. For example, the units for molarity (moles of solute per liter of solution) are mol/L, while the units for mass percent (mass of solute per 100g of solution) are %.

4. How can I convert between different units of concentration?

To convert between different units of concentration, you can use conversion factors or dimensional analysis. Make sure to pay attention to the units and use proper conversion factors.

5. How does concentration affect solubility?

The higher the concentration of a solute in a solution, the more likely it is to reach its saturation point and no longer dissolve. However, different solutes have different solubilities, so concentration is just one factor that can affect solubility.

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