Download Unit 7 Overview

Unit 7
Electrochemistry
Objective: To become familiar with the basic function of an electrochemical cell
(battery)
Electrochemistry Project
Chapter 19 Sections 2 and 3
Oxidations and reductions involve the escape of electrons from molecules or
ions of one substance and their capture by other chemical substances. Oxidationreduction (redox) reactions are important because they are the principal sources of
energy on this planet, both natural or biological and artificial. Oxidation of molecules by
removal of hydrogen or combination with oxygen normally liberates large quantities of
energy and forms water. This is the principle by which hydrogen fuel cell cars operate.
The synthesis of reduced organic molecules (sugars) by photosynthetic green plants is
an example of another redox reaction and the main device for trapping and storing solar
energy on this planet.
Redox reactions release energy, and this energy can be used to do work if the
reactions take place in a voltaic cell. In a voltaic cell (sometimes called a galvanic cell),
the transfer of electrons occurs through an external pathway (a wire) instead of directly
between the two elements. This movement of electrons through the wire is defined as
electricity, which can be harnessed to power a multitude of devices. In this unit, we will
explore the inner workings of a battery, and by doing so will gain a deeper
understanding of the inner workings of redox chemistry.
In this unit, make sure that you can say with confidence…
I can…
1.
2.
3.
4.
5.
Identify the anode and cathode and describe how they are assigned.
Describe a half-cell, the chemistry within, and write the chemical equation.
Explain how a salt bridge works.
Explain why some batteries produce more voltage than others.
Describe why a battery will eventually stop working.