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Author Topic: What solute particles are present?  (Read 34121 times)

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A5HLEY

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What solute particles are present?
« on: October 08, 2007, 04:30:01 PM »

Hi all, I'm new to the forum and also a struggling chemistry student. :) I appreciate any input that I get in advance.

Ok, so this is not urgent... it isn't a homework problem. Our teacher suggests that we work problems in our book in an effort to prepare for exams, so I'm just trying to get ahead of the game. This week we've been talking about electrolytes, and this problem focuses on electrolytes and solute particles.

Here we go:

a). Acetone, CH3COCH3, is a nonelectrolyte; hypochlorous acid, HClO is a weak electrolyte; and ammonium chloride, NH4Cl, is a strong electrolyte. What are the solute particles present in aqueous solutions of each compound? (Select all that apply.)

Acetone
H+
CH3COCH3
CH3CCH3 2+
CH3COCH2 -
O2 -

Hypochlorous acid
H+
O2-
HClO
HCl 2+
ClO -

Ammonium chloride
HCl
NH3
Cl -
H +
NH4 +
NH4Cl

[Ok, so I understand that an electrolyte is a substance containing free ions, but I'm just confused as to how you can tell WHICH ions.]

b). If .1 mol of each compound is dissolved in solution, which one contains .2 mol of solute particles, which contains .1 mol of solute particles, and which contains somewhere between .1 and .2 mol of solute particles?

[I really have no idea about this one. I'm assuming it has something to do with the solubility of each, but I'm not entirely sure.]
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Yggdrasil

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Re: What solute particles are present?
« Reply #1 on: October 08, 2007, 04:55:12 PM »

A nonelectrolyte does not dissociate into ions in solution.  A weak electrolyte partially dissociates, so you will have a mixture of your original salt and the ions that it dissociates into.  A strong electrolyte dissociates completely so that none of the original material is left and all that remains are the ions that it's composed of.

Given this information can you make some guesses?
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A5HLEY

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Re: What solute particles are present?
« Reply #2 on: October 08, 2007, 05:02:13 PM »

A nonelectrolyte does not dissociate into ions in solution.  A weak electrolyte partially dissociates, so you will have a mixture of your original salt and the ions that it dissociates into.  A strong electrolyte dissociates completely so that none of the original material is left and all that remains are the ions that it's composed of.

Given this information can you make some guesses?

So perhaps the acetone is only CH3COCH3, the hypochlorous acid is H+ and ClO -, and the ammonium chloride is NH4+ and Cl- ?
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Yggdrasil

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Re: What solute particles are present?
« Reply #3 on: October 08, 2007, 05:04:32 PM »

For a weak electrolyte, the dissociation is incomplete.  So, while some of the HClO will dissociate into H+ and ClO-, a good portion of it will remain as HClO in solution.
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A5HLEY

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Re: What solute particles are present?
« Reply #4 on: October 08, 2007, 05:23:39 PM »

For a weak electrolyte, the dissociation is incomplete.  So, while some of the HClO will dissociate into H+ and ClO-, a good portion of it will remain as HClO in solution.

So how do you determine which has which amount of mols when placed in solution? I think acetone would be .2 mol solute particles, since it dissolves without producing ions. Maybe hypochlorus acid would be between .1 and .2, and ammonium chloride would be .1 mol? Correct me if I'm wrong...
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Yggdrasil

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Re: What solute particles are present?
« Reply #5 on: October 08, 2007, 05:46:09 PM »

So if you put 0.1mol of acetone in solution, what are the 0.2mol of solute particles?
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Borek

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Re: What solute particles are present?
« Reply #6 on: October 08, 2007, 09:37:52 PM »

So how do you determine which has which amount of mols when placed in solution?

Note: for now don't bother with concentration of ions in weak electrolytes, that's completely different subject. But you may safely try to find out concentrations in strong electrolytes and in non-electrolytes. Now, go back to Ygg question if you have not yet answered it ;)
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