Identifying Species

When we do redox reactions, sometimes it is difficult/uncertain which species have been produced. We have other chemical tests to help us confirm which species (ions/molecules) are present. We do not need to write equations for these in the assessment for this topic, but they are worth knowing anyway...

One species not mentioned here is copper (II), Cu²⁺:

Adding NaOH:
Cu²⁺ + 2OH^- --> Cu(OH)₂
This is a blue precipitate.

Adding excess NH₃ solution:
Cu²⁺ + 4NH₃ <--> [Cu(NH₃)₄]²⁺
This is a royal blue solution.

Redox Reactions

Over the next few lessons, we will be carrying out some redox reactions and justifying why they are indeed redox. This is very similar to the assessment task in the last week of term.

Redox Equations Tutorials

Redox Tutorials

Mr Nicoll is away for the week, so the following videos have been made available to help with the work in class:

Electron Transfer
Oxidation-reduction is another class of reaction that we need to know about. What is oxidation-reduction? It is a reaction where electrons are transferred.

Oxidation and Reduction
Oxidation and reduction are complementary processes. When one occurs, the other must also occur.

Oxidation Numbers
One way to determine whether oxidation-reduction has occurred or not is to see if the oxidation number of a species has changed. Oxidation numbers also tell us what has been oxidised and what has been reduced.