ES 2 - Redox

Question 1

What is electrolysis?

Answer 1

Electrolysis is the breaking down of a substance using electrical energy

Question 2

How is electrolysis done in the lab?

Answer 2

Two non-reactive electrodes are connected to the power supply and placed in the solution, the power is turned on and electrolysis starts

Question 3

How does electrolysis work?

Answer 3

The cations (positive ions) are attracted to the cathode (the negatively charged electrode) and are reduced. |The anions (negative ions) are attracted to the anode (the positively charged electrode) and oxidised. The compound is therefore broken up as the two ions do not need each other to be stable

Question 4

What is a half equation?

Answer 4

A half equation shows the reaction that happens at the one electrode in an electrolysis reaction
2Cl - (aq) ==> Cl2 (g) + 2e -

Question 5

What is an oxidising agent?

Answer 5

An oxidising agent is a substance that removes electrons from other species by accepting electrons and getting reduced

Question 6

What is a reducing agent?

Answer 6

A reducing agent is a substance that donated electrons to other species by getting oxidised

Question 7

What does the Roman Numeral indicate in copper (I) sulfide?

Answer 7

It indicates that the oxidation number of copper is +1. We can therefore infer that the formula of the compound is Cu2S

Question 8

What does the Roman Numeral indicate in sodium chlorate (I)?

Answer 8

It indicates that the oxidation number of chlorine is +1 in the compound. The oxidation numbers of oxygen and sodium do not change very often so we can assume that they are -2 and +1 respectively. We can therefore infer that the formula of the compound is NaClO