Time Estimate:  2:30

Equipment Needed:

Hot Plates are needed
Buretts and clamps
Thermometers
Stirring Rods
250 mL Erlenmeyer Flasks
400 mL Beakers
100 mL Graduated Cylinders

Chemicals Needed:

KMnO₄ solution - ( Harriman: This solution is stored in bench
door.  When the lab is finished, refill the carboy with 0.1 N
solution. )

 Preparation of KMnO₄ (FM = 159.0 g/mol) solution:

 This is the same as a 0.0200 M solution -
 For a 10 L carboy - use 31.8 g of KMnO₄.  Stir thoroughly
and place the carboy in a dark place to allow settling of
some MnO₂ which is formed.

Na₂C₂O₄ solid  - (they should use ~0.200 g per determination in
about 30 - 50 mL 0.5 M H₂SO₄)

0.5 M H₂SO₄  - 10 L jug - To be placed on front bench.

85% H₃PO₄  To be placed on front bench.

Unknown - solid Ferrous Ammonium Sulfate (?H₂O) in bottle labeled
"Unknown"

Place Na₂C₂O₄   and Fe sample (unknown) next to balances.

Special Precautions:

Waste management - Tell the students to pour their unused KMnO₄
into a container that you put out.  We can use this for future
labs.

Place large beakers on the bench for used waste.  Neutralize
waste when finished.

For those who have no space to write down their final answers,
have them report the % Fe next to the last check point.

Suggested Instructions:

Have them look at problem 14 of previous lab for guidance for
the present lab.  Be sure that they don't take more than approx
0.25 g of oxalate.

If they have not done problem 14, they should do it before
beginning the laboratory