Name: ………………………………………… Grade: …………………

Practical No : ……………. Date: ………………….

The electrolysis of Copper Sulphate.

This is a demonstration experiment in which the educator conducts the experiment and learners observe and record results.

AIMS:

1. To demonstrate the electrolysis of a solution of copper sulphate using copper electrodes.2. To show an understanding of the chemical processes involved in electrolysis.3. To establish the change in masses of the respective electrodes.

INSTRUCTIONS:

1. Take notes when the procedure is explained to you in class so that you will be able to include the theory in your write-up.

2. Record all the results obtained in the experiment.3. Explain the theory of electrolysis in your write-up.4. Consult the rubrics to ensure that you have included all that is expected of you.

PROCEDURE:

1. Describe the action plan, including a statement of the problem, the apparatus that you would use, a sketch of the apparatus and circuit diagram and the method that you will follow.

2. Write a brief explanation of the electrolysis process that occurs in this experiment. Head this section “Theory of Electrolysis”. Use point form in all explanations.

3. Draw up a suitable table for the readings to be entered into, and enter these readings.4. State the conclusion to the investigation, and discuss possible sources of error.5. Attach the rubric sheet to the top of your write-up.

ASSESSMENT:

The rubrics on the next page will be used to assess your work. The total number of marks for the practical is given on the rubric sheet.

NAME: ……………………………………………………. CLASS: ……….. DATE …………………..

ASSESSMENT RUBRICS FOR THE ELECTROLYSIS OF COPPER SULPHATE: Prac No: …..

Assessment of investigative and manipulative skills

CRITERIA

COMPETENCY LEVEL

Not achieved

1

Partially achieved

2

Achieved

3States the problem

1 2 3

Presents action plan1 2 3

Presents list of apparatus and a sketch with circuit diagram 1 2 3

(12)Assessment of ability to explain electrolysis

CRITERIA Competency level

Fully explained, including the half-reactions and full equation. Clear understanding demonstrated 4

Fair explanation, but an error or omission.3

A number of errors or omissions. Little real understanding 2

Very poor explanation. No real understanding demonstrated.1

(4)Assessment of recording skill

CRITERIA Competency level

All readings neatly tabulated in a neat, logical manner.4

Readings tabulated, but not in a logical or clear manner3

No structure shown in recording of readings.2

Readings not recorded1

(4)Assessment of interpretation of data

CRITERIA Competency level

Correctly uses data to change in mass of electrodes. Steps clearly identifiable and explanation given where necessary. 4Correct calculation but weakness in methodical setting out of the calculation.

3Very poor setting out. Logical steps not evident, even though calculation may be correct. 2Calculations not attempted. 1

(4) Total Marks : 24 Mark Achieved: ……………

Sample results obtained during the electrolysis of copper sulphate:

Current allowed to flow for 15 minutes.

Strength of current flow = 0.7A

Initial mass of Cu anode = 71.59 g and Cu cathode = 73.6 g

Final mass of Cu anode = 71.39 g and Cu cathode = 73.8 g

Apparatus for demonstrating the electrolysis of Copper Sulphate