General and Inorganic Chemistry

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General and Inorganic Chemistry

• Prof. Maurizio Paci
• Email paci_at_uniroma2.it
• Phone [phone]

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Chemistry and Matter

• Chemistry
• The study of properties of materials and of
  changes that materials undergo
• Matter
• Its the physical material of universe anything
  that occupies space and has mass
• Matter can exist in three physical states
  (aggregation states)
• Gas o vapor
• Liquid
• Solid

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Introduction to Matter
Gas No fixed volume or shape it conforms to the
volume and shape of its container. Gases can be
compressed or expanded to occupy different
volumes Liquid A liquid has a fixed volume,
independent of its container, but it has no
specific shape. It assumes the shape of the
container it is in. Liquids cannot be appreciably
compressed Solid A solid has its own defined
volume and shape. Solids cannot be appreciably
compressed
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Introduction to Matter
Substance A pure substance has a fixed
composition and distinct properties. Most matter
we come in contact with in daily life is not a
pure substance but a mixture of different
substances Physical and Chemical Properties Every
pure substance has a unique set of defined
properties characteristics which allow us to
distinguish it from other substances. These
properties fall into two general categories
physical and chemical. Changes can be macroscopic
or microscopic Chemical Properties properties
that we can measure without changing the basic
identity (the composition) Chemical Properties
describe the way a substance can change or react
to form other substances
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Introduction to Matter
Physical and Chemical Changes Substances can
undergo several changes in properties these
changes can be classified as either chemical or
physical Physical changes changing the physical
appearance but not the basic identity. All
changes of state (e.g. solid, liqid or gas) are
physical changes Chemical changes also known as
chemical reactions. Changing the basic identity
the substance is tranformed into different
chemically substances .
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Introduction to Matter
Mixtures Mixtures refer to combination of two or
more pure substances in which each substance
retain its own chemical identity and hence its
own properties Heterogeneous mixtures are not
uniform throughout the sample and have regions of
different appareance and properties Homogeneous
mixtures are uniform throughout the sample,
however the individual substances retain their
individual chemical and physical nature.
Homogeneous mixtures are also called solutions.
The most common type is descrbed by a solid (the
solute) that is dissolved in a liquid (the
solvent) An important characteristic of
homogeneous mixtures is that individual
components retain their chemical and physical
properties. Thus, its possible to separate the
substances based on their different physical
properties For example, we can separate water
from ethanol using heir different boiling
temperatures in a process known as distillation.
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Elements and compounds
Pure substances have an invariable composition
and are composed by either elements or
compounds Elements Substances that cannot be
decomposed into simpler substances by chemical
means Compounds Can be decomposed into two or
more elements, by which that substance is
constituetd.
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Elements and compounds
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Elements and compounds

• Elements
• Elements are the basic substances out of which
  all matter is composed
• Everything in the worls is made up of only 109
  different elements
• 90 of the human body is composed by only three
  elements Oxygen, Carbon and Hydrogen
• Elements are known by a common name as well as
  their abbreviation.

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Element Abbreviation
Carbon C
Fluorine F
Hydrogen H
Iodine I
Nitrogen N
Oxygen O
Phosphorus P
Sulfur S
Aluminum Al
Barium Ba
Calcium Ca
Chlorine Cl
Helium He
Magnesium Mg
Platinum Pt
Silicon Si
Copper Cu (from cuprum)
Iron Fe (from ferrum)
Lead Pb (from plumbum)
Mercury Hg (from hydrargyrum)
Potassium K (from kalium)
Silver Ag (from argentum)
Sodium Na (from natrium)
Tin Sn (from stannum)
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Elements and compounds
Compounds Compounds are substances composed by
two or more elements. In a compound the
constituting elements are chemically united and
are combined in a definite proportion by mass.
The observation that the elemental composition
of a pure compound is always the same is known
as the law of constant composition ( or the law
of definite proportions). For example, pure
water is composed by two elements, Oxygen and
Hydrogen, at the defined ratio of 11 Hydrogen
and 89 Oxygen. In one kg of water we find 110 g
of H and 890 g of O. In 20 g of water there are
2.2 g of H and 17.8 g of O