This aesthetic, in-depth, neatly typed document summarises Section F of the IEB Grade 12 Chemistry syllabus: Electrochemistry. This document includes the full Section F syllabus, all definitions, additional class notes, own research notes and all relevant diagrams.
Redox reaction: Reaction involving the transfer of electrons
• Oxidation is the loss of electrons
OIL RIG : Oxidation is Loss, Reduction is Gain
• Reduction is the gain of electrons
• Oxidising agent: Substance that accepts (takes) electrons (Causes other species to lose electrons)
• Reducing agent: Substance that donates (gives) electrons (Causes other species to gain electrons)
Writing balanced equations using half reactions:
• A half reaction contains electrons:
- Either on the left of arrow (reduction)
- Or on the right of arrow (oxidation)
• Net reactions must NOT show any electrons
Li+ + e¡ ! Li Li ! Li+ + e¡
f
f
e on the left of e on the right of
arrow = reduction arrow = oxidation
reaction reaction
Electrolysis: Transfer of electrons
REDOX
!
!
reduction oxidation
1. Gaining of electrons 1. Loss of electrons
2. Reduction (decrease) in 2. Increase in
oxidation number oxidation number
, Electrolytic cells:
• Electrode reactions that are sustained by a supply of electrical energy (not spontaneous) (electrode
must be solid conductor: graphite/metal)
• Conversion of electrical energy into chemical energy
Processes and Redox reactions:
• Identify anode and cathode
Anode: Where oxidation takes place
Cathode: Where reduction takes place
• Write half reaction equations taking place at anode and cathode
• Write net ionic cell reaction (combine 2 half reactions)
• Identify oxidising and reducing agent for electrolytic reaction
• Identify or suggest suitable inert electrodes (don't react)
Electrolyte: A substance (liquid) that can conduct electricity by forming free ions when molten or
dissolved in solution
• Identify predominant half-reaction taking place at anode and cathode during electrolysis of
AQUEOUS solution
• Strongest RA or OA present in solution will be oxidised or reduced during electrolysis. Except
when their concentration becomes too low
• Role of concentration when predicting predominant anode half-reaction:
- When concentration of weak RA is HIGH, then it will undergo oxidation in preference to a strong
RA.
• Anode itself will be oxidised in preference to the ions:
- When electrode material is a stronger RA than ions in solution
- When graphite electrodes in Hall-Heroult cell react with oxygen
• Inherent reactivity (electrode potentials) will determine which half-reaction will be predominant at
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Lindyprinsloo. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $4.00. You're not tied to anything after your purchase.
