Chemistry How many moles of ions are present in 250mL of 4.4 M solution of sodium sulfate?

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To determine the number of moles of ions in a 250 mL solution of 4.4 M sodium sulfate, one must first calculate the moles of sodium sulfate, which equals 1.1 mol. However, since sodium sulfate dissociates into three ions (two Na+ and one SO4^2-), the total number of moles of ions is 3.3 mol. Additionally, a separate question about producing hydrogen gas from water decomposition highlights the need to understand the number of electrons required for each H2 molecule, which is two. The forum emphasizes the importance of following rules and guidelines for effective communication.
Asian Girl
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I thought this is a pretty easy problem and I can't believe I did it wrong. What did I do wrong?

How many moles of ions are present in 250mL of 4.4 M solution of sodium sulfate?

Here what I did:
250 mL = .25 L
mol Na2(SO)4 = MV = 4.4 * .25 = 1.1 mol

but the answer was 3.3 mol
 
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Because the question asks how many ions are present, you need to multiply the moles of sodium sulfate by the number of ions it breaks down into in water.

In this case, I believe the Na2(SO)4 will dissociate to make two Na+ ions and one (SO)4 ion (total of 3 ions).
 
altegron said:
Because the question asks how many ions are present, you need to multiply the moles of sodium sulfate by the number of ions it breaks down into in water.

In this case, I believe the Na2(SO)4 will dissociate to make two Na+ ions and one (SO)4 ion (total of 3 ions).

Thanks
 
Another one:
Water can be decomposed by the passage of an electric current according to the equation 2H2O (l) ---> 2H2 (g) + O2 (g)
How many moles of H2 (g) can be produced from the passage of 4.8*10^21 electrons?

I solved:
4.8*10^21 / 6.022*10^23 * 2 = 1.6*10^-2 mol

What did I do wrong?
 
How many electrons needed per each H2 molecule?

Borek
 
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yea really I need answer for her question fast :S I have OLYMPIAD Tomorrow. Thanks :smile:
 


Which question?
 
Last edited by a moderator:


ElectroBoss said:
yea really I need answer for her question fast :S I have OLYMPIAD Tomorrow. Thanks :smile:
I'm sorry, but this forum does not work that way. Please read the forum rules first.
 

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