Hazards
Nickel, copper, cobalt and chromium salts are toxic. Do not ingest.
Materials
- HP Spectrophotometer
- cuvettes
- splitter cable for monitor
Procedure
- Arrange to borrow one of the HP spectrophotometers from the Chem 161/Chem 317 lab.
- Attach a splitter cable to the monitor jack and connect the monitor to the Imager projector interface box.
- Turn on the spectrophotometer.
- Type in uv and hit return.
- Choose F1 for general scanning.
- Choose F2 and type in the wavelength range 420 to 820.
- Choose F5 to select the Overlay mode of presentation.
- Place a blank in the sample holder and choose F8 to scan the blank.
- Replace the blank with your sample and press F1 to scan.
The spectrophotometer shows the absorption spectra of each colored solution. Sample spectra are shown in the demo write-up book.
Sample solutions
To show nickel complexes
- green: \( \ce{Ni(H20)62+_{(aq)} } \)
- blue: \( \ce{Ni(NH3)62+_{(aq)} } \)
- purple: \( \ce{Ni(en)32+_{(aq)} } \)
To show copper sulfate vs copper ammine
- pale blue: copper sulfate solution aq.
- super blue: \( \ce{Cu(NH3)62+_{(aq)} } \)
To show variously colored substances
- green: \( \ce{Ni(H20)62+_{(aq)} } \)
- super blue: \( \ce{Cu(NH3)62+_{(aq)} } \)
- purple: crystal violet (aq)
- pink: \( \ce{Co(H20)62+(aq) } \)
- orange: potassium dichromate. aq.