Transcript Document 7828883

WUJUD ZAT
Oleh
A. Sjaifullah
Kimia adalah
Pengetahuan yang mempelajari materi
dan perubahannya
Materi adalah
Apapaun yang memiliki massa dan
menempati ruang
Teori Kinetik
Semua partikel (atoms, molekul
dan ion) menyusun materi
selalu bergerak secara random
dan berinteraksi
Wujud zat
Cara menyusun partikel
Energi partikel
Interaksi/jarak antar partikel
Karakteristik wujud zat
Sifat partikel
gerakan
wujud Proximity Energy
padat
close
little
vibrational
cair
close
moderate rotational
gas
far apart
a lot
translational
Volume
definite
definite
indefinite
bentuk
definite
indefinite
indefinite
Jika kondisi partikel (susunan,
interaksi dan energi) diubah,
maka terjadi perubahan wujud
posisi partikel-partikel zat cair & gas tidak tetap,
Zat cair dan gas dapat dialirkan/berdifusi =(fluida)
Perubahan wujud terjadi dalam siklus air di alam
Sifat-sifat gas
Salah satu sifat gas adalah dapat memberikan tekanan.
Tekanan gas terjadi akbat
dari tumbukan partikelpartikel gas dengan
dinding
Tekanan yang disebabkan
oleh campuran gas-gas yang
ada di udara disebut tekanan
atmosfir
Tekanan adalah…..
Mengapa tekanan udara sangat penting?
·Adanya angin
·Menciptakan mendung dan awan
Hubungan tekanan dan volume gas
Hukum Boyle
P1V1 = P2V2
Volume and Temperature
Hukum Charles
V1
T1
V2
=
T2
, tekanan tetap
Korek gas, hair spray, tabung LPG
akan terasa lebih dingin jika
digunakan,
Karena……………..
Karena partikel gas hampir tidak
berinteraksi satu sama lain, jumlah partikel
(molekul) gas hanya bisa ditentukan/diukur
pada volume, tekanan dan suhu tertentu
Persamaan keadaan gas ideal.
Volume molar gas pada STP
Zat Cair
Properties of Liquids
• Surface tension: the
energy required to
increase the surface area
of a liquid by a unit
amount.
• Viscosity: a measure of a
liquid’s resistance to flow.
Tekanan Uap Cairan
ZAT PADAT
Karena interaksi yang kuat, posisi partikel-partikel dalam zat
padat tidak berubah terhadap satu dengan yang lain
Amorf
Kristal
Comparison: Amorphous solids
Tar, molten glass, molten plastics,
and molten butter, consist of large
molecules or a mixture of
molecules that cannot move
readily. As the temperature is
lowered, their molecules move
more and more slowly and finally
stop in random positions. The
resulting materials are called
amorphous solids or glasses.
Such solids lack an ordered
internal structure. Common
examples include candle wax,
butter, glass, and plastics.
Crystals are classified into systems
based on the angle their bonds form.
*7 common systems
Isometric, Hexagonal, Tetragonal, Trigonal,
Triclinic, Monoclinic, Orthorhombic
What crystal system does this
mineral belong to? Why?
Quartz
Hexagonal
•3 equilateral axes
intersect at angels of
60o , 1 vertical axis
intersect at 90o to
equilateral axes.
•Hexa-six
Beryl
http://www.minerals.net/glossary/glossary.htm
What crystal system does this
mineral belong to? Why?
MONOCLINIC
• 3 unequal axes and
1 unequal
intersection that is
not at 90o
• Mono-one
http://www.minerals.net/glossary/glossary.htm
GYPSUM
What crystal system does this
mineral belong to? Why?
Sugar
Isometric
• 3 axes are at right
angles, all sides equal
length.
• Iso- same
http://www.minerals.net/glossary/glossary.htm
What crystal system does this
mineral belong to? Why?
Tetragonal
• 3 axes are at
right angels, only
2 lateral axes are
equal length and
it has 4 sides.
• Tetra-four
WULFENITE
http://www.minerals.net/glossary/glossary.htm
What crystal system does this
mineral belong to? Why?
TANZANITE
ORTHORHOMBIC
• 3 unequal axes all at right
angles to each other
• Ortho-unequal
http://www.minerals.net/glossary/glossary.htm
What crystal system does this
mineral belong to? Why?
Amazonite
Trigonal
• 3 equal length axes, 3 equal
intersections (not 90o)
• Tri- three
Note:
Hexagonal but
with 3 sides not
6
http://www.minerals.net/glossary/glossary.htm
What crystal system does this
mineral belong to? Why?
Triclinic
• 3 unequal axes and 3 unequal
intersections not at 90o
• Tri-three
http://www.minerals.net/glossary/glossary.htm
Using your 3-D structures identify
the following into rightful system:
Picture 1
Isometric
Picture 2
Tetragonal
Picture 3
Hexagonal
Picture 5
ORTHORHOMBIC
Picture 6
MONOCLINIC
Picture 7
TRICLINIC
Picture 4
Trigonal
Crystal Systems
System
Axes
Angles
Unique Symmetry
Diagram
Examples
Isometric
a=b=c
===90°
Four 3-fold
Pyrite, Halite, Galena, Garnet,
Diamond, Fluorite
Tetragonal
a=bc
===90°
One 4-fold
Wulfenite, Rutile, Zircon,
Chalcopyrite
Hexagonal
a=bc
=120°, ==90°
One 6-fold
Quartz, Beryl (Emerald), Apatite,
Corundum (Ruby, Sapphire)
Orthorhombic
abc
===90°
Three 2-fold
Sulfur, Barite, Olivine, Topaz
Monoclinic
abc
==90°, 90°
One 2-fold
Orthoclase, Malachite, Azurite,
Mica, Gypsum , Talc
Triclinic
abc
90°
None
Turquoise, Kyanite, Albite,
Plagioclase
Crystal Systems
System
Isometric
Tetragonal
Hexagonal
Orthorhombic
Monoclinic
Triclinic
Axes
Angles
Unique Symmetry
Diagram
Examples
STRUCTURE OF OTHER SYSTEMS
• Struktur NaCl
SOME DEFINITIONS …
• Lattice: 3D array of regularly
spaced points
• Crystalline material: atoms
situated in a repeating 3D
periodic array over large atomic
distances
• Amorphous material: material
with no such order
• Hard sphere representation:
atoms denoted by hard, touching
spheres
• Reduced sphere representation
• Unit cell: basic building block unit
(such as a flooring tile) that
repeats in space to create the
crystal structure; it is usually a
parallelepiped or prizm
SIMPLE CUBIC STRUCTURE (SC)
• Cubic unit cell is 3D repeat unit
• Rare (only Po has this structure)
• Close-packed directions (directions along which atoms touch each other)
are cube edges.
• Coordination # = 6
(# nearest neighbors)
(Courtesy P.M. Anderson)
ATOMIC PACKING FACTOR
• Fill a box with hard spheres
– Packing factor = total volume of spheres in
box / volume of box
– Question: what is the maximum packing factor
you can expect?
• In crystalline materials:
– Atomic packing factor = total volume of atoms
in unit cell / volume of unit cell
– (as unit cell repeats in space)
ATOMIC PACKING FACTOR
a
R=0.5a
close-packed directions
contains 8 x 1/8 =
1 atom/unit cell
Adapted from Fig. 3.19,
Callister 6e.
Lattice constant
• APF for a simple cubic structure = 0.52
BODY CENTERED CUBIC
STRUCTURE (BCC)
• Coordination # = 8
(Courtesy P.M. Anderson)
Adapted from Fig. 3.2,
Callister 6e.
• Close packed directions are cube diagonals.
--Note: All atoms are identical; the center atom is shaded
differently only for ease of viewing.
ATOMIC PACKING FACTOR: BCC
R
Adapted from
Fig. 3.2,
Callister 6e.
Unit cell contains:
1 + 8 x 1/8
= 2 atoms/unit cell
a
• APF for a body-centered cubic structure = p3/8 = 0.68
FACE CENTERED CUBIC
STRUCTURE (FCC)
• Coordination # = 12
Adapted from Fig. 3.1(a),
(Courtesy P.M. Anderson)
Callister 6e.
• Close packed directions are face diagonals.
--Note: All atoms are identical; the face-centered atoms are shaded
differently only for ease of viewing.
ATOMIC PACKING FACTOR: FCC
a
Unit cell contains:
6 x 1/2 + 8 x 1/8
= 4 atoms/unit cell
Adapted from
Fig. 3.1(a),
Callister 6e.
• APF for a body-centered cubic structure = p/(32) = 0.74
(best possible packing of identical spheres)
FCC STACKING SEQUENCE
• FCC Unit Cell
• ABCABC... Stacking Sequence
• 2D Projection
A
A sites
B sites
C sites
A
B
B
C
B
C
B
B
C
B
B
HEXAGONAL CLOSE-PACKED
STRUCTURE (HCP)
Ideally, c/a = 1.633 for close packing
However, in most metals, c/a ratio deviates from this value
HEXAGONAL CLOSE-PACKED
STRUCTURE (HCP)
• ABAB... Stacking Sequence
• 3D Projection
• 2D Projection
A sites
B sites
A sites
Adapted from Fig. 3.3,
Callister 6e.
• Coordination # = 12
• APF = 0.74, for ideal c/a ratio of 1.633
STATES OF MATTER
• The Four States of Matter
• Solid
• Liquid
• Gas
• Plasma
• Four States
Kinetic Theory of Matter
Matter is made up of particles
which are in continual random
motion.
STATES OF MATTER
SOLIDS
•Particles of solids are
tightly packed, vibrating
about a fixed position.
•Solids have a definite
shape and a definite
volume.
Heat
STATES OF MATTER
LIQUID
 Particles of liquids are
tightly packed, but are
far enough apart to
slide over one another.
 Liquids have an
indefinite shape and a
definite volume.
Heat
STATES OF MATTER
GAS
 Particles of
gases are very far
apart and move
freely.
 Gases have an
indefinite shape
and an indefinite
volume.
Heat
PHASE CHANGES
Description of
Phase Change
Solid to
liquid
Term for Phase
Change
Melting
Liquid to
Freezing
solid
Heat Movement During
Phase Change
Heat goes into
the solid as it
melts.
Heat leaves the
liquid as it
freezes.
PHASE CHANGES
Description of
Phase Change
Liquid to
gas
Term for Phase
Change
Vaporization,
which includes Heat goes into the
boiling and
liquid as it vaporizes.
evaporation
Gas to liquid Condensation
Solid to gas
Heat Movement During
Phase Change
Sublimation
Heat leaves the gas
as it condenses.
Heat goes into the
solid as it sublimates.
STATES OF MATTER
PLASMA
 A plasma is an
ionized gas.
 A plasma is a very
good conductor of
electricity and is
affected by
magnetic fields.
 Plasmas, like gases • Plasma is the
have an indefinite
common state
shape and an
of matter
indefinite volume.
STATES OF MATTER
SOLID
Tightly packed, in
a regular pattern
Vibrate, but do not
move from place
to place
LIQUID
Close together
with no regular
arrangement.
Vibrate, move
about, and slide
past each other
GAS
Well separated
with no regular
arrangement.
Vibrate and move
freely at high
speeds
PLASMA
Has no definite
volume or shape
and is composed
of electrical
charged particles
Some places where plasmas are found…
1. Flames
2. Lightning
3. Aurora (Northern Lights)
The Sun is an example of a star in its
plasma state
COLD PLASMA
COLD PLASMA PEN