Clarification details
Updated March 2016. This document has been updated in its entirety.
This standard involves demonstrating understanding of oxidation-reduction processes.
Demonstrating understanding
The intent of the standard is to demonstrate understanding of oxidation-reduction processes. Regardless of any practical components which may be carried out, students need access to correct observations for the reactions being assessed.
Making judgements
For all levels of achievement, students need to identify what has been oxidised and reduced for both cell types, support with descriptions of either loss / gain of electrons or oxidation number changes. Some reference to the requirement of energy for an electrolytic cell and a link to reduction potentials or cell potential for electrochemical cells.
Merit also requires students to give balanced half equations for both cell types and link these to observations and explain spontaneity of electrolytic and electrochemical cells with reference to reduction potentials or cell potential calculations, using appropriate chemical terminology and conventions.
Excellence also requires students to compare and contrast the oxidation-reduction processes occurring in electrolytic and electrochemical cells, including elaborating on the spontaneity of the reactions using reduction potentials or cell potential calculations and fully balanced equations.