Inquiry question: How do the properties of substances help us to classify and separate
them?
explore homogeneous
mixtures and
heterogeneous mixtures
through practical
investigations:
using separation
techniques based on
physical
properties(ACSCH026)
Separation techniques: Separation of mixtures are
based on different physical properties of the
components in a mixture Physical properties are
properties that can be observed or measured without
changing chemical nature of matter, for example:
colour, smell, melting point, boiling point, etc.
There are a variety of separation techniques which
uses the different types of physical properties to
separate mixtures
calculating percentage
composition by weight
of component
elements and/or
compounds(ACSCH007)
Percentage composition Gravimetric analysis is determining the quantities (mass) of substances
present in a mixture, and expressing it as a weight percentage This involves separating the mixture
and accurately measuring the mass along the way, so that you can calculate the composition of the
mixture Uses of gravimetric analysis: - Percentage by weight of different ingredients in food -
Whether an ore can be mined economically The percentage composition of each
element/compound can be calculated using: w/w% = final mass (element/compound) initial mass
(mixture) × 100%
Background
Information:
The particle theory states that all matter consists of very small particles, which are constantly
moving Elements are pure substances that cannot be decomposed into simpler substance. They are
homogenous (uniform composition) Compounds are pure substances composed of two or more
different types of elements chemically bonded together in a fixed ratio. They are also homogenous
Mixtures are made up of two or more different types of elements or compounds mixed together (ie
NOT chemically bonded) - As such, they can be separated by physical means - This also means that
mixtures CANNOT be represented by a chemical formula Mixtures are classified into homogenous
or heterogenous
Homogeneous
The components that make up homogenous mixtures are uniformly distributed. That is, they have
the same uniform appearance and composition throughout Examples of homogenous mixture
include: - Air - Steel - Salt water
Heterogeneous
A heterogenous mixture is simply any mixture that
is not uniform in composition This means they
have localised regions with different properties and
thus different samples taken from the mixture are
not identical to each other Examples of
heterogenous mixture include: - Sand - Pizza - Mixed
nuts
investigate the
nomenclature of inorganic
substances using
International Union of Pure
and Applied Chemistry
(IUPAC) naming
conventions
classify the elements based
on their properties and
position in the periodic table
through their:
physical properties
Physical properties are properties that
can be observed or measured without
changing the chemical nature of matter
They can be described as either intrusive
or extrusive - Intrusive physical properties
will remain the same regardless of the
amount matter. For example: density,
colour, etc - Extrusive physical properties
are dependent on the amount of matter.
For example: mass, volume, length etc.
Physical properties The elements of
the periodic table can be divided into
three main groups: Semi-metals: - B,
Si, Ge, As, Sb, Te, Po Metals: -
Everything to the left of semi-metals
Non-metals: - Everything to the right
of semi-metals Elements in each of
the above categories will have similar
physical properties
Physical properties of metals:
Generally shiny/lustrous
appearance Solids at room
temperature moderate to high
melting and boiling points Good
conductors of heat and
temperature Malleable (can be
shaped without breaking) and
ductile (can be drawn into wires
without breaking) Typically high
density
Physical properties of
non-metals: Generally have a
dull appearance A range of
melting and boiling points
Quite brittle generally not
malleable/ductile
Physical properties of
semi-metals: Semi-metals
have properties that fall
between metals and non-metals
chemical
properties
A chemical property is a characteristic
or behavior of a substance that may
be observed when it undergoes a
chemical change or reaction The
chemical property of an element is
dependent on the type of element,
electrons, and bonding between
particles Recall that an element is
made up of only one type of atom
Atomic
structure and
atomic mass
Inquiry question:
Why are atoms of
elements different
from one another?
investigate the basic
structure of stable and
unstable isotopes by
examining:
their position in
the periodic table
The vertical columns in the period table
are called groups - Elements of the same
group has the same number of electrons
in their outermost (valence) electron shell
- Eg, both sodium and lithium (group 1
elements) has only 1 electron in its
valence shell - The elements between
group 2 and 3 are known as transition
elements
The horizontal rows in the
period table are called
periods - Elements of the
same period has the same
number of electron shell
the distribution of
electrons, protons
and neutrons in
the atom
representation of the
symbol, atomic number
and mass number
(nucleon number)
model the atom’s
discrete energy
levels, including
electronic
configuration and
spdf notation
calculate the
relative atomic mass
from isotopic
composition
investigate energy
levels in atoms and
ions through:
collecting primary data
from a flame test using
different ionic solutions
of metals
examining spectral
evidence for the
Bohr model and
introducing the
Schrödinger model
investigate the properties of unstable isotopes
using natural and human-made radioisotopes
as examples, including but not limited to:
types of radiation
types of balanced nuclear reactions
Periodicity
Inquiry question: Are there patterns in the properties of elements?
demonstrate, explain and predict the
relationships in the observable trends
in the physical and chemical
properties of elements in periods and
groups in the periodic table, including
but not limited to:
state of
matter at
room
temperature
electronic
configurations and
atomic radii
first ionisation
energy and
electronegativity
reactivity with water
Bonding
Inquiry question:
What binds
atoms together in
elements and
compounds?