Electrochemistry Test
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Posljednje ažuriranje over 5 years ago
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Formulae and equations
When you are writing formulae and equations, you need to write your answer in such a way that the computer will recognise your answer. Please following the following instructions:
- Separate all substances with a space (E.g. 4Na + 2O2 --> 2Na2O)
- No space between the stoichiometric number and the compound/ion/element
- The arrow must be formed like this --> It is two dashes and a greater than sign.
- Any charges must be placed in a round bracket, e.g. SO4(2-) for sulfate, H(+) for hydrogen ions, and e(-) for electrons.
- Do not put in state symbols unless asked.
Example: 2ClO3(-) + 12H(+) + 10e(-) --> Cl2 + 6H2O
Diagrams
One question will ask you to draw a diagram. Please draw it on paper, take a picture of it, send it to your computer, and upload it using the function. If you really want to draw it using your mouse, you can, but I definitely don't recommend it.
Marking
Your teacher will mark questions 7, 11, 12 and 13. These questions are written questions and a diagram.
Calculate the e.m.f of the cell.
Write a half equation for the oxidation process occuring at the negative electrode of this cell.
Write an equation for the spontaneous reaction that occurs
Give one reason why the e.m.f. of the cell changes when the electrodes are connected and a current flows.
State how, if at all, the e.m.f. of this standard cell will change if the surface area of each platinum electrode is doubled.
State how, if at all, the e.m.f. of this cell will change if the concentration of IO3- ions is increased.
Explain your answer to the previous question.
Use the data given in the table at the top of the section to determine the vanadium species present in the solution at the end of this reaction.
State the oxidation state of vanadium in this species
Write a half-equation for its formation from V2+ (aq).
The standard electrode potential for the reduction of iron(III) ions into iron(II) ions can be measured by connecting a suitable electrode to a standard hydrogen electrode. Draw a clearly labelled diagram to show the components and reagents, including their concentrations, in this Fe(III)/Fe(II) electrode. Do not draw the salt bridge or the standard hydrogen electrode.
State the purpose of the salt bridge.
State one essential requirement of the soluble ionic compound used to make the salt bridge.
Which ion cannot catalyst the reaction between iodide and peroxodisulfate (S2O82-)?
Use the table above to answer the question.
The following cell has an EMF of +0.46 V.
Cu| Cu2+ || Ag+ | Ag
Which state is correct about the operation of the cell?
In this question, consider the data above.
The e.m.f. of the cell Ag | Ag+ || Pb2+ |Pb is...
In this question consider the data above.
The e.m.f. of the cell Pt | H2 | H+ || Ag+ | Ag would be increased by...
A disproportionation reaction occurs when a species M+ spontaneously undergoes simultaneous oxidation and reduction. The table above contains E data for copper and mercury species.
Using these data, which one of the following can be predicted?
Based on the above data, which one of the following could reduce 0.012 mol of bromine to bromide ions?
The most powerful oxidising agent in the table is:
Use the data in the table above to answer this question.
Which of the following statements is not correct?