MATTER

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MATTER
AND

• CHANGE

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Chemistry

• The study of matter and the changes it undergoes.

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Matter

• Anything that has mass and takes up space

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Alchemical view of matter
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Matter

• Atoms are the building blocks of matter

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Matter
Space-filling models of molecules
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Matter
Oxygen
Hydrogen
Each element is made of the same kind of atom
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Each element is made of the same kind of atom
with unique set of properties
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Carbon
Uncut diamond
Graphite
Uncut diamond with impurities
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STATES OF MATTER Solid, Liquid, Gas
(a) Particles in solid (b) Particles in
liquid (c) Particles in gas
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STATES OF MATTER

• SOLIDS
• Definite shape and volume
• Particles of a solid packed tightly together
• NOT easily compressed

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SOLIDS
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STATES OF MATTER

• LIQUIDS
• Particles in close contact but arrangement is not
  orderly or fixed
• Definite volume
• NOT easily compressed

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Liquid
In a liquid

• molecules are in
• constant motion
• there are appreciable
• intermolecular forces
• molecules are close
• together
• Liquids are almost
• incompressible
• Liquids do not fill the
• container

H2O(l) Water
Zumdahl, Zumdahl, DeCoste, World of Chemistry
2002, page 31
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STATES OF MATTER

• GAS
• Particles NOT in close contact and are constantly
  moving
• No definite volume

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Some Properties of Solids, Liquids, and Gases
Property Solid Liquid
Gas
Shape Has definite shape Takes the shape
of Takes the shape the container
of its container Volume Has a definite
volume Has a definite volume Fills the volume
of the container Arrangement
of Fixed, very close Random, close
Random, far apart Particles Interactions between
Very strong Strong Essentially
none particles
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How to describe matter

• Extensive properties
• Depends on the AMOUNT of matter in a sample
• Mass
• Volume

• Intensive properties
• Depends on the TYPE of matter in a sample
• Color
• Temperature
• Density

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SUBSTANCE

• Matter that has a uniform and definite
  composition
• Every sample of a given substance has identical
  intensive properties because every sample has the
  same composition
• Elements CANNOT be broken down into simpler
  components
• Compounds CAN be broken down into elements

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Examples of pure substances
GOLD
ALUMINUM
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Compounds

• Made of two or more different kinds of elements
  chemically combined in a fixed proportion.
• for example
• Common table salt is a one to one combination of
  sodium atoms (Na) and chlorine atoms (Cl) NaCl

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What do we mean by chemically combined?

• Elements in compounds are joined by chemical
  bonds.
• Examples of chemical bonds
• Ionic bond (electrostatic attraction that binds
  oppositely charged ions)
• Usually composed of metal and nonmetal atoms
• Covalent bond (bond that forms by the sharing of
  electrons between atoms)
• Usually composed of carbon atoms bonded to
  elements such as hydrogen, oxygen, nitrogen and
  sulfur

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Properties of Compounds

• Compounds can be broken down into simpler
  substances by chemical means but elements cannot.
• Compounds and the elements from which they are
  formed have different properties

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Examples of Compounds

• Sugar (sucrose)
• Composed of carbon, hydrogen and oxygen
• Sugar a sweet-tasting white solid but carbon is a
  black, tasteless solid Hydrogen and oxygen are
  odorless gasses
• Sugar Carbon Water

http//www.youtube.com/watch?vA_jtOpAYG70
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Sugar (sucrose)
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Sugar (sucrose)
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Properties of Matter

• Physical properties
• Can be observed without changing a substance into
  another substance
• Boiling point, density, mass, volume, magnetic

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Properties of Matter

• Physical changes
• Changes in matter that do NOT change the
  composition of a substance
• Changes of state (liquid to a gas), temperature
  (melting point), volume, crush, grind
• Chemical changes
• Changes that result in a new substance
• Combustion, oxidation, decomposition

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Mixtures

• Physical blend of two or more components
• Heterogeneous composition is variable
  throughout the sample
• Homogeneous composition is uniform throughout
  the sample

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Classification of Matter