chapter 2 - part 1 - analysing matter
TRANSCRIPT
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MatterMatter
y The particles can be atoms, molecules or ions.
Atom Molecule Ion
The atom is the
smallest, indivisible
particle of an element.
Atoms of the same
element are exactlyalike and are different
from the atoms of all
other elements.
Molecules are the
smallest particles of an
element or compound
that are made up of
two or more atoms.
Ions are particles that
are charged due to
loss or gain of
electrons.
Ions which arepositively charged are
called cations.
Ions which are
negatively charged are
called anions.
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ExamplesExamples
Atom Liquid Gas
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Element and CompoundElement and Compound
y Elements can exist as atom, molecule or
ion.
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y Chemical element is the class of atomswith the same number of protons in the
nucleus.
y An element consists of only one type of
atom.
y Element can be either atoms or
molecules.
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CompoundCompound
y Compound can be molecule or ion.
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y A compound is any substance composed
of identical molecules consisting of atoms
of two or more elements.
y A compound is made up of either
molecules or ions.
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The particle theory of matterThe particle theory of matter
y The particle theory of matter states that
matter is made up of a large number of
tiny and discrete particles.
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DiffusionDiffusion
y Diffusion is a process resulting from random motion of
molecules by which there is a net flow of matter from a
region of high concentration to a region of low
concentration.
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Example of diffusionExample of diffusion
y Diffusion in Solid
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y Copper(II) sulphate crystals are made of
copper(II) ions and sulphate ions which are tinyand discrete.
y The particles in the copper(II) sulphate crystal
will separate to become ions and diffuse
randomly upwards until the whole agar turnsblue.
y Diffusion of solid is defined operationally as the
random movement of particles to all directions
in a solid.
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Diffusion in LiquidDiffusion in Liquid
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y Diffusion has taken place in the liquid.
y
The rate of diffusion of the particles inwater is faster than the diffusion rate of
particles in solid.
y The occurrence of diffusion proves that
potassium permanganate(VII) consist of
tiny and discrete particles.
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Diffusion in GasDiffusion in Gas
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y Bromine vapour is made of tiny and
discrete molecules that move randomlyto fill up space.
y Bromine vapour moves randomly anddiffuses in all directions in air from areas
of higher concentration to areas of lower
concentration.
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Brownian motionBrownian motion
y Brownian motion is the physical phenomenon
that minute particles immersed in a fluid move
about randomly.
y It was named for the Scottish botanist Robert
Brown, the first to study such fluctuations
y Brownian movement, an example of diffusion,
supports the kinetic theory of matter.
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Examples ofBrownian movement are
y movement of smoke particles in air
y movement of pollen grains in water
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KineticTheory ofMatterKineticTheory ofMatter
y The characteristics of matter can be
described using the kinetic theory of
matter.
y The kinetic theory of matter explains the
state of matter in solid, liquid and gaseous
states based on the following
assumptions:
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y The gas consists of very small particles,
each of which has a mass.
y These molecules are in constant, random
motion.
y The rapidly moving particles constantly
collide with each other and with the wallsof the container.
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y There are forces of attraction between
particles of matter.y These attraction forces will increase as the
distance between the particles becomes
closer.
y The average kinetic energy of the gasparticles depends only on the temperature
of the system.
y
The higher the temperature, the higher thekinetic energy of the particles.