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Topic: Another Ksp Related Question  (Read 3850 times)

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dagr8est

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Another Ksp Related Question
« on: April 09, 2006, 02:19:19 PM »
Sigh, I am starting to think that every answer on this answer key is wrong...  If someone can confirm that I did this question correctly, I will just disregard the answer key for the rest of the questions.

***

Calculate the Ag+ concentration required to start a precipitation of AgBrO3 from a solution containing 0.50g of NaBrO3 per 0.300 litre.  Ksp of AgBrO3 = 5.3(10-5)

***

[BrO3-] = [NaBrO3] = 0.50g(1mol/127.9g)(1/0.300L) = 0.013M

Ksp = [Ag+][BrO3-]
5.3(10-5) = [Ag+](0.013M)
4.1(10-3)M = [Ag+]

Answer key says it's 4.5(10-11)M...
« Last Edit: April 09, 2006, 02:20:51 PM by dagr8est »
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Offline Borek

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Re: Another Ksp Related Question
« Reply #1 on: April 09, 2006, 02:52:45 PM »
Seems to me it should be 4.8*10-3, so both answers are wrong. Check molar mass of sodium bromate.
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dagr8est

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Re: Another Ksp Related Question
« Reply #2 on: April 09, 2006, 03:15:42 PM »
Oh yeah whoops, I forgot to include sodium.  I agree it should be 4.8(10^-3)M then.  I guess this answer key is just completely wrong then.  Thanks for the help on both questions. ;D
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Offline AWK

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Re: Another Ksp Related Question
« Reply #3 on: April 10, 2006, 12:15:47 AM »
MM  of NaBrO3 is ~ 151
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