01. Revision of Matter and Materials.ppt

Revision

1. Matter
• Matter is described as anything that has
a mass and occupies a space.
• There are three states of matter:
Solid, liquid and gas.
• All that you see around you is made of
some kind of material or other.
• All materials are thus made of matter.
Solids, liquids & gases
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2. Matter & materials
 All objects are either made from natural
or man-made (artificial) materials
 Properties depend on composition of
material & uses of the material depend
upon its properties
 Physical properties: appearance,
strength, electrical & heat conductivity
 Chemical properties: how substances
react in chemical reactions.
States of matter
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3. Mixtures
Mixtures are combinations of 2 or more
substances that maintain their physical
properties and may be separated by
physical means. i.e. screws and nails in a
bowl may be separated by hand.
There are 2 types of mixtures:
 Homogeneous mixtures &
 Heterogeneous mixtures
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4. Homogeneous Mixtures
• Have uniform composition
• Can’t visually distinguish components
of mixture
• Often in the same phase
Examples: salt water
air
alcohol & water
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5. Heterogeneous Mixtures
• No uniform composition
• Can visually distinguish components
• Sometimes in different phases
Examples: oil & water
muddy water
sulphur & iron filings
Fe + S
Separating oil & water
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6. Separation of mixtures
Mixtures can be separated by physical
means i.e. magnetism, boiling points,
solubility etc.
How could the following be separated?
Sulphur & iron filings
Water and alcohol
Muddy water
Salty water
Nails & screws
Water & salt separation
Fe & S separation
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7. Chromatography
This occurs when ink is separated into the
different colours making up the ink.
Chromatography
Absorbent paper with ink marks
Solvent: mixture of ethanol & water
The different colours travel through the paper at
different speeds.Different effects:
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8. Pure substances
Pure substances consist of only one type
of substance and can’t be separated by
physical means.
Elements and compounds are pure
substances.
Elements: gold, copper, oxygen, iron etc.
Compounds: water, table salt,
copper sulphate & sugar
Compounds & mixtures
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9. Elements & compounds
Elements can’t be broken down into simpler
substances. They consist of atoms.
Compounds are made of 2 or more elements
& can be broken down (by chemical means)
into the elements making up the compound.
Compounds usually consist of molecules or
formula units. The elements making up the
compound always occur in a fixed ratio.
Elements & compounds
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10. Elements
Elements are classified according to their
chemical properties and their structures.
Elements consist of:
Metals (about 80)
Metalloids (or semi-metals – about 7)
Non-metals (about 20)
Elements are arranged in the periodic
table according to their structures.
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11. General properties of elements
 Metals on left of table – usually hard, shiny
& good conductors of electricity & heat.
 Non-metals on right of table – usually softer,
dull in colour & don’t conduct electricity or
heat.
 Metalloids have properties of both metals
and non-metals & situated in a diagonal down
the table next to the non-metals
 Metalloids can conduct electricity under
certain conditions & are called
semiconductors Periodic table
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12. Classification of elements
Write down the symbols & names of:
3 metalloids:
7 non-metals:
15 metals
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13. Electrical conductivity of elements
Some metals conduct well: Cu, Ag
Some not so well: Ni, Zn & Cr
Conductivity of metals decreases with an
increase in temperature.
Conductivity of metalloids usually
increase with an increase in temperature.
Conductivity
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14. Insulators
Metals have electrons available to allow
electrical conductivity.
Non-metals do not have electrons available
to allow electrical conduction & are poor
conductors.
Materials that do not allow electrical
conduction are called insulators
Insulators: glass, wood, china,
sulphur.
Conductors & insulators
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15. Thermal conductors & insulators
Diamond
Silver & copper
Aluminium, steel
Lead
Ice, marble, glass
Human tissue (excluding blood)
Rubber, wood
Polystyrene
Cork, wool
air
Worst
conductor
Best
conductor
Worst
insulator
Best
insulator
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16. Great insulation!
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17. Hot water
C
uB
rass
G
lass
A
lFe
Unmelted
wax
Melted
wax
Different rods are connected to a trough containing
hot water. The rods were dipped into molten wax &
the wax was allowed to solidify on the rods.
Discuss the heat conductivity of these rods.
Conduction of heat
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18. Magnetic and non-magnetic
materials
Only 3 really important magnetic
materials:
Iron, nickel &cobalt
All other materials are less non-
magnetic: zinc, wood, paper etc
Substances affected
by magnets
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19. Compounds
Compounds are named according to
the elements making up the compound
and we use formulae to represent the
compound.
Sodium chloride: NaCl
Magnesium oxide: MgO
Copper sulphate: CuSO
4
NaCl CuSO
4
CO
2 MgO
Compounds
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