A student investigates the electrolysis of silver nitrate solution using silver electrodes which take part in the reaction.
She uses this method:
The ionic half-equations for the reactions at the electrodes are:
Suggest why the silver strips would dry more quickly when washed with propanone rather than with water.
The student's results are shown in the table:
| Electrode | Mass of electrode before electrolysis in g\text{g}g | Mass of electrode after electrolysis in g\text{g}g |
|---|---|---|
| Positive electrode | 12.4512.4512.45 | 11.8511.8511.85 |
| Negative electrode | 10.3010.3010.30 | 10.8410.8410.84 |
(i) Calculate the increase in mass, in grams, of the negative electrode.
Suggest two reasons why the increase in mass of the negative electrode was less than the decrease in mass of the positive electrode.
Another student investigated the effect of changing the electrical charge, in faradays, passed during the electrolysis. One faraday is the electrical charge of one mole of electrons. Their results are shown in the table:
| Experiment | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | | :--- | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | | Electrical charge in faradays | 0.01 | 0.02 | 0.03 | 0.04 | 0.05 | 0.06 | 0.07 | 0.08 | 0.09 | | Increase in mass in g\text{g}g | 1.08 | 2.16 | 3.24 | 5.10 | 5.40 | 6.48 | 7.56 | 8.64 | 9.72 |
Identify which experiment gave an anomalous result.
Suggest why a line of best fit plotted for this data should go through the origin (0,0)(0,0)(0,0).
Explain how the data shows that the increase in mass is directly proportional to the electrical charge passed.
Calculate the expected increase in mass, in grams, of the negative silver electrode if an electrical charge of 0.110.110.11 faradays was passed.
