Silver Precipitates

 

Hazards: 

Avoid contact with silver compounds as they will stain skin and clothing.

Chemicals and Solutions: 

0.1 M Na2CO3             ( 1 mL)

0.1 M AgNO3              (10 mL)

0.1 M NaOH               (10 mL)

0.1 M NaCl                 (30mL)

5 M NH3                             (35 mL)

0.1 M NaBr                 (10 mL)

0.1 M Na2S2O3                (50 mL)

0.1 M KI                     (10 mL)

Materials: 

600 mL beaker

200 mL water

Magnetic stirrer and bar

Procedure: 

Add 200 mL and a stirring bar to the 600 mL beaker and begin stirring.

Starting with 1 mL of sodium carbonate add the solutions consecutively to the water in the order listed in the materials section.  Precipitates will form and disappear.

Hint: 

Discussion: 

Precipitate

Color

Ksp

Moles/L

Ag2CO3

white

8.1 x 10-12

1.2 x 10-4

most soluble

AgOH

brown

6.8 x 10-9

8.2 x 10-5

AgCl

white

1.8 x 10-10

1.3 x 10-5

AgBr

yellow

7.7 x 10-13

8.8 x 10-7

AgI

yellow

8.3 x 10-16

1.2 x 10-8

least soluble

2Ag+ + CO32- ---> AgCO3 (white solid)

Ag2CO3 + 2OH- ---> 2AgOH + CO32- (brown solid)

AgOH + Cl- ---> AgCl + OH- (white solid)

AgCl + 2NH3 ----> Ag(NH3)2+ + Cl- (colorless)

Ag(NH3)2 + + Br- ---> AgBr + 2NH3 (yellow solid)

AgBr + 2S2O32- ---> Ag(S2O3)23- + Br-(colorless)

Ag(S2O3)23- + I- ---> AgI + 2S2O32-(yellow)

 

Hazards:  Avoid contact with silver compounds, they will stain skin and clothing

 

 

 

To schedule a demonstration, please send an email to the demonstration lab.

 

Contact:

Eric Camp

Lecture Demonstration Technician

Bagley Hall 171

(206) 543-1606

ericcamp@uw.edu

 

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