Experiment 11 Electrolysis Electrolytic Cells

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Experiment 11Electrolysis - (Electrolytic Cells)

• Students will work in groups of 6.

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Solutions for the Electrolysis part are located
in front of the dispensary.
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Calculate the volume of 1 M CuSO4 and 1 M H2SO4
required to make a 200 mL solution, which
consists of 0.1 M CuSO4 and 0.01 M H2SO4. Have
your calculations checked by your TA!
Pour the calculated volume of 1 M CuSO4 into the
cylinder, add the calculated volume of 1 M H2SO4
to the same cylinder.
Return to your lab bench and pour the contents of
the graduated cylinder into a 250 mL beaker. Make
the volume up to 200 mL with water.
Take a 25 mL graduated cylinder to the dispensary
bench.
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Pour this solution into the electrolysis cup.
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Polish two copper electrodes with rounded ends,
wash with water, rinse with acetone, air dry.
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Label each electrode and weigh them on the
analytical balance to 0.0001g
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Put a spin bar in the cup
and place this cell on a magnetic stirrer at a
medium setting.
Clamp the electrodes, rounded ends down, onto the
electrode holder, and place the holder onto the
electrolysis cup.
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Measure the calculated amount of 0.1 M H2SO4 to
prepare 400 mL of 0.1 M H2SO4 with a 50 mL
graduated cylinder. Pour it into an 800 mL beaker
and make the volume up to 400 mL with distilled
water.
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Moisten your hand with water and place the index
or the middle finger on the eudiometer tube .
Fill the eudiometer tube with the prepared 0.1 M
H2SO4 solution, and leave the rest of the
solution in the 800 mL beaker.
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Invert the eudiometer tube into the 800 mL beaker.
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Support the tube using a burette clamp on a lab
stand.
No air bubbles should be in the tube!
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Insert the brass electrode so the curved end is
inside the opening of the eudiometer tube.
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And set the carbon electrode in the 800 mL beaker.
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Using the electrical leads provided, connect the
cells, the power supply and the ammeter.
Attention DO NOT plug in the power supply until
your TA has inspected the apparatus. There is
possibility of electric shock if the connections
are made incorrectly!
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Adjust the eudiometer tube so that the level of
solution inside the tube is even with the level
of solution in the beaker and record the volume
of H2.
When the volume of H2 collected is 95 to 100 mL,
turn of the current and record the volume.
Turn on the power supply record the initial time
and current, then record the time, current and
volume every 5 minutes.
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Rinse the copper electrodes very carefully with
acetone, and weigh them when dry.