H Writing

Date: 2015-10-07; view: 496.

UNIT 6

To explain what chemistry involves it is helpful to consider certain factors. To begin with, what chemists do and what they are interested in will be examined and then three important areas of chemistry will be clarified.

A simple definition of chemistry is that it is a discipline that looks at what exists in our world and finds out what it is made of and what it can do. From ancient times, people saw that burning matter transformed its structure and combining different substances produced new materials such as iron and glass. Moreover, at this time alchemists (early chemists) experimenting to produce gold, discovered many chemical processes that chemists still use nowadays.

In more modern times, there were three developments, which define what chemistry is. Firstly, in the eighteenth century Lavoisier and Lomonosov came up with the idea of the conservation of mass. Basically, however a substance was changed (by heating, for instance), their quantity and mass remained the same. Furthermore, in the nineteenth century, Dalton put forward the idea that all matter consisted of atoms but it took another century for scientists like Curie, Rutherford and Bohr to prove atomic structure. Finally, Mendeleev, working on Dalton's theory, classified each element according to their atomic weight and chemical properties and produced a table, which is very important to science.

To sum up, the three developments outlined above define chemistry. We now understand it is the science which examines the composition, structure and properties of substances and the ways in which they can be changed.