SUMMARY

Redox: Electrochemical Cells

Introduction- Electricity on the Move

Batteries are vital for a whole variety of portable electric and electrical gadgets:

laptop computers, mobile phones, personal stereos and camcorders

1

A half cell consists of…..A metal in contact with a solution of its own ions

2

The salt bridge connects……

The ions in the two half cells

3

The wire connects the two different half cells allowing…..

The flow of electrons

4

Half cells develop electrical potential because of…..

The tendency of all metals to give away electrons

5

If two half cells are connected by a votmeter and salt bridge….

Their potential difference(e.m.f) can be measured

6

If the other half cell is a standard hydrogen elctrode, the measured emf is called…

Eo (E standard)

7

Eo values are measured at standard conditions which are …..

1mol/dm3 solutions, 100 Kpa pressure and 298K temperature

8

Eo values for half cells are listed in order, with the most negative(the best electron releasers) at the top, to give…..

The electrochemical series

9

The electrochemical series can be extended to systems other than metal/metal ion by…..

Making electrical contact with a platinum electrode

10

Half cells high in the electrochemical series can transfer electrons to …..

Half cells lower in the list

11

The feasibility of reactions can be predicted by …..

The anticlockwise rule

12

The feasibility of reactions can also be predicted by….

Calculating Eo reaction

13

This is done by …..Adding together two half reactions and their Eo values

14

In order for the electrons in the half reactions to cancel out ….

one of the half reactions must be reversed (and thus the sign of its Eo value changed )

15

If the reaction is feasible….

Eo reaction is positive usually greater than 0.4V.