Cliffs AP Chemistry, 3rd Edition

It is the uncomplexed Cu2+(aq)ion concentration that needs to be determined through the

Nernst equation

..

]

]

[

EE log log[

n QE Cu

0 0592 Zn

2

00 0 0592

2

2

==--+

+

..

[]

VV. log

Cu

056 =- 110 0 0592 2 12 +

[ +]

log.

Cu

(^1) 18 2
2 =
[ +]
.
Cu
(^12) =175 10# (^18) M- 1
[Cu2+] = 5.71 × 10 –19M
Since 20. drops = 1 mL, 1 drop = 0.050 mL; and 2 drops were added, V 1 = 0.10 mL
[)]Cu NH( 3 42 + ==VM^11 ##V 2 010. 10 1mL. mL^10. M=0 010. M
The formation constant, Kf, is derived from the following equation:
Cu 4 NH! Cu NH()
2

• (^334)
  ++ 2
  ]
  )]
  ..

..
[][

[(

K

Cu NH

Cu NH

571 10 60

0 0099 14 10

f^44194

13

2

3

3

##

== =#

+

+ -

2

_ i ^ h

%%exp. %%
exp
error
obs
100
210

1 3 10 2 10 100 3

13

13 13

#

#

= - = ##- # =-

Laboratory Experiments