What is matter?
by George
E. Hrabovsky, President MAST
You will notice that I ask numerous questions and number
them. I have no intention of answering these questions in
sequence. The numbering is a bookkeeping device so that I
can keep track of things. The point of this column is to investigate
what heat is, and I will only go so far afield from that goal.
This means that some questions will go unanswered. This is
reasonable, and it allows for future projects based on those
unanswered questions. Feel free to attempt to answer these
questions for yourself.
We have covered what heat is, and we have learned what spaces
are. Now we need to get back to physics.
To answer this question I introduce the chemistry book by
Linus Pauling [1],
where the first chapter deals extensively with this question. Pauling
defines matter as any mass-energy moving at less than the
speed of light (as opposed to radiant energy which does move
at the speed of light). He goes on to describe the kinds
of matter as substances. This raises the questions:
30. What is mass-energy?
31. What is the speed of light?
A substance is a collection of matter whose elements have
the same properties. Substances have a definite composition. They
can further be separated into elemental substances or compound
substances. An elemental substance is made up of atoms
of the same kind. A compound substance is made up of
atoms of different kinds. Thus oxygen gas consists of
oxygen atoms and is an elemental substance, while water consists
of atoms of hydrogen and oxygen and is a compound substance
(or just a compound). This raises the questions:
32. What are the properties of matter?
33. What is an atom?
34. How do atoms make matter?
The definition above gives the impression that all matter
within an object will have the same properties. This
is a definition of homogeneous
matter. We can also have matter that is composed
of parts that have different properties. This is called heterogeneous
matter. Heterogeneous matter is further divided
into solutions and mixtures.
Solutions are often homogeneous, though they are not considered
to be substances. Other forms of heterogeneous matter
are called mixtures.
35. What are the properties
of matter?
A phase is a homogeneous part of matter separated from other
matter by some physical boundary. Examples of phases
are solids, liquids, gases, plasmas, and even more exotic
forms of matter.
36. What is a physical boundary?
37. What is a solid?
38. What is a liquid?
39. What is a gas?
40. What is a plasma?
41. What are exotic forms of matter?
A mixture can be composed of different components, all of
which have the same phase (for example a mixture of sulfuric
acid and water as a liquid), or different components can be
in different phases (for example, gas dissolved in water).
Book Review: General Chemistry
Linus Pauling, "General Chemistry,"
W. H. Freeman and Company (1970, reprinted by Dover Publications
in 1998).
This is, in my opinion, the
best beginning chemistry book. It was written by one of the
greatest chemists of the last century. The first six
chapters describe the properties of matter, including an introduction
to atomic and molecular structure. Chapters 7 and 8 introduce
some principles of organic chemistry. Chapter 9 introduces
the properties of gases, quantum mechanics (including the
Schrödinger equation), and statistical mechanics. Chapter
10 covers chemical thermodynamics and applies quantum mechanics
and statistical mechanics to molecular systems. Chapter
11, which is all about chemical equilibrium introduces the
Van der Waals equation of state. Chapter 12 introduces
the chemistry of a truly weird substance: water. Chapter
13 introduces the chemistry of substances and colloids (another
example of a mixed phase mixture). Chapter 14 is an introduction
to the chemistry of acids and bases, including titration. Chapter
15 introduces the concepts of oxidation-reduction reactions
and electrolysis, including metallurgy. Chapter 16 introduces
the rate of chemical reactions, including chain reactions. Chapters
17 through 22 introduce inorganic chemistry by each inorganic
elemental group in the periodic table. Chapter 23 completes
the introduction to organic chemistry. Chapter 24 introduces
biochemistry. The last two chapters introduce the
chemistry and physics of nuclei and elementary particles.
References
[1]: Linus Pauling, "General Chemistry,"
W. H. Freeman and Company (1970, reprinted by Dover Publications
in 1998).
Created by Mathematica
(January 18, 2005) 
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