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Topic: what is the new concentration of Cu++  (Read 3755 times)

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Offline michenll

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what is the new concentration of Cu++
« on: July 08, 2010, 01:18:23 AM »
10 ml of NH4OH 5M added to       80 ml of Cu2+ 0.1M

the reaction:

Cu2+ +4NH4OH(aq) <---> Cu(NH3)4 +4H2O


what is the new concentration of Cu++

equilibriumu K=21000
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Offline AWK

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Re: what is the new concentration of Cu++
« Reply #1 on: July 08, 2010, 03:05:00 AM »
Show your attempt!
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Offline Tahk

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Re: what is the new concentration of Cu++
« Reply #2 on: July 08, 2010, 08:09:31 AM »
OK,

moles of cu2+ = c*v=0.1*0.08=0.008moles
moles of NH4OH  = c*v=5*0.01=0.05moles

Cu2+ +4NH4OH(aq)
1        :4
0.008   : 0.05
-0.008 : -0.0125

and I get that the4NH4OH(aq) is extra...

but in the second qoatuon I need to use again in the ions of Cu so I undedstand that I have a problem
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Offline AWK

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Re: what is the new concentration of Cu++
« Reply #3 on: July 09, 2010, 04:23:09 AM »
Quote
Cu2+ +4NH4OH(aq) <---> Cu(NH3)4 +4H2O

0.008   : 0.05
-0.008 : -0.0125

Write down an expression for formation constant and put known data (concentrations) into it
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