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Introduction
 Introduction
Resource- This unit is an introduction to
chemistry concepts, using water as the main illustration. Much of the
unit is devoted to exploring the smallest water particle – a water
molecule – what it is and how it...
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1 The power of water
- 1 The power of water Resource
- The ways in which human activities
interact with the water cycle can have devastating consequences for all
forms of life. These range from the very large scale – for example, the
effects of the movement...
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2 Earth's store of water
- 2.1 Where water occurs and how we
measure it Resource
- When astronauts first ventured to
the Moon in the late 1960s, they were captivated by a vision of the
Earth in colour as it had never been seen before (Figure 2). It is not
surprising that, after pictures...
- 2.2 Going up: using scientific
notation for large numbers Resource
- Think again about the value for
the total volume of water stored on Earth: 1460 000 000 km3.
- 2.3 The study of a raindrop Resource
- Most of the usable water is
derived from the 1.1 × 105 km3 that falls over the land surface each
year as rain, snow, sleet or hail. The collective term for all of these
sources of water is precipitation....
- 2.4 Going down: using scientific
notation for small numbers Resource
- You saw in Section 2.2 how the
powers of ten notation provides a concise method of expressing very
large numbers and reduces the chances of errors when, otherwise, many
zeros would have to be written out....
- 2.5 What is water made of? Resource
- The size of a water droplet may
seem very small but in terms of the scale of scientific measurement it
is relatively large. You already know that water is made up of molecules
so now consider a water droplet...
- 2.6 Models of a water molecule Resource
- In this kind of building set,
there are a limited number of types of block and each block has a
particular shape. Just as importantly, each one has a particular way in
which it can link to other blocks...
- 2.7 The ‘salt’ in seawater Resource
- The difficulty with having so much
of the Earth's water locked up in the oceans is summed up poetically by
Coleridge's ‘Ancient Mariner’, becalmed on board ship in the doldrums,
beneath a blazing Sun.
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3 What are compounds?
- 3 What are compounds? Resource
- Click on the video clip to watch
Elements and Compounds, which focuses on water and its constituent
elements.
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4 Inside the atom
- 4 Inside the atom Resource
- Before going on to see how atoms
can link (bond) with each other, you need to look at atoms in a little
more detail. Doubtless they are not like blocks of Lego! So what are
they like?
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5 Molecules and covalent bonding
- 5 Molecules and covalent bonding Resource
- Covalent bonding is one kind of
linking that joins atoms together. The group of atoms held together by
covalent bonds is a molecule. The example you are most familiar with is
the compound water: water...
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6 Chemical language
- 6.1 Introduction Resource
- The previous sections in this unit
include many terms which may have been unfamiliar to you: for example,
atom, element, compound, molecule and bond. Chemistry has a language all
of its own and grasping...
- 6.2 Chemical symbols Resource
- So far, atoms have been
represented as labelled spheres or circles and the bonds that link atoms
in molecules have been represented as lines. This is a rather
cumbersome method of writing down molecules....
- 6.3 Chemical formulas Resource
- By using symbols, elements can be
represented much more conveniently and much more briefly. This method of
using symbols can be extended to compounds. You will now look further
into this idea using a very...
- 6.4 Chemical equations and chemical
reactions Resource
- The previous section shows how
different elements can either exist on their own or combine with other
elements to make compounds. This section builds on these ideas by
looking at chemical reactions in...
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7 Ions and ionic bonding
- 7 Ions and ionic bonding Resource
- This section returns to bonding –
the way in which atoms are joined to each other. You have already met
one type of bonding involving covalent bonds, which is found in
molecules. However, this is not the...
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8 Water and its impurities
- 8 Water and its impurities Resource
- Water must be of a certain quality
to be suitable for human consumption. No natural water found on Earth
is pure; any sample of water contains more than just water molecules.
Some materials, such as sodium...
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9 Unit summary
- 9 Unit summary Resource
- You have learned about the
following concepts in this unit:
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References and Acknowledgements
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