CHEMISTRY chemical cells and batteries

Cell - two electrodes in an electrolyte used to generate electricity

Battery - Two or more chemical cells connected together

Electrolyte - a liquid that conducts electricity

eg) Salt solution; the ions can move freely in the solution allowing them to carry a charge.

What factors affect the voltage produced by a cell?

1) The metals used; the greater the difference in reactivity between the two metals, the higher the voltage.

2) The electrolyte; Changing the electrolyte and/or the concentration of the electrolyte can affect the voltage

Voltage produced by many chemical cells is typically 1.5 volts.

To increase the voltage, you can connect several cells together. A 6 volt battery is made up of 4 1.5 volt cells connected together.

A battery is two or more cells connected together in series.

As a current is drawn from a cell, the chemicals inside it get used up. In non-rechargeable cells, once one or more of the reactants has been used up, the battery is 'flat' and stops working.

Examples of non-rechargeable cells are lithium button cells, and alkaline cells.

In rechargeable cells and batteries, the chemical reactions can be reversed to re-form these chemicals. This means they can be used over and over again. The chemical reactions in a cell can be reversed by passing an electric current through the cell.

Cells and batteries advantages

1) they provide a very convenient portable source of electricity, which can be used in many devices.

2) They are relatively cheap

Disadvantages

1) Many cells contain toxic chemicals which can harm the environment if these chemicals are not recycled.