Chapter 17
Study Guide
Matter
Matter is classified as substances and
mixtures.
Matter has mass and takes up space
Mixture – composition variable, can be
separated by a physical means
Element – composition definite
Compound – two or more elements
combined
Pure Substances
Element
matter composed of identical atoms
All atoms are the same
EX: copper
Classifying Matter
Colloid vs. Solution-pass a beam of light
through the mixture
If the beam is invisible- it is a solution
If the beam is visible- it is a colloid
 The visible beam through the colloid is called the
Tyndall effect
Suspension- heterogeneous mixture
containing a liquid in which visible particles
settle out over time – like dirty water and
Italian salad dressing
Mixtures
Variable combination of 2 or more pure
substances.
Homogeneous Mixture (AKA -Solution)
even distribution of components
very small particles
particles never settle
EX: saline solution, fresh pickle juice
Mixtures
Heterogeneous Mixture
uneven distribution of components
colloids and suspensions
EX: granite
Pure Substances
Compound
matter composed of 2 or more
elements in a fixed ratio
properties differ from those of
individual elements
NOT a mixture
EX: salt (NaCl)
Mixtures
Colloid
medium-sized particles
Tyndall effect - particles scatter
light (looks cloudy)
particles never settle
EX: milk, fog
Tyndall Effect
Because of
the Tyndall
effect, A light
beam is
Scattered by
the Colloid
suspension
On the right,
but Passes
invisibly
Through the
solution
On the left.
Physical Properties
 Physical Property- any characteristic of a
material that you can observe or attempt to
observe without changing the identity of the
substance
For example: color, shape, size, melting point,
and boiling point, how it flows.
Metallic aluminum: Silvery color, easily formed,
reflects heat.
 Behavior of substances- magnetism,
ductility- ability of metal to be drawn into
wires; malleability- ability of metal to be
shaped- pounded into sheets; ability to flow
Physical Change
A change in the form of a substance
without changing its identity.
properties remain the same
reversible
can be used to separate mixtures
EX: dissolving, grinding, distillation, mixing
sugar and salt
Physical Changes
Distillation- separating a solution of two
liquids through evaporating
a liquid and
re-condensing
its vapor.
Vapors from the liquid
with the lowest boiling
point form first and are
condensed and
collected
Chemical Property
A characteristic that indicates whether
a substance can undergo a specific
chemical change.
EX: flammability, reactivity, resistance of a
diamond to corrosion
Chemical changes can be used to separate
substances- done in labs- metals can be
removed from ore this way
Chemical and Physical Weathering
WeatheringPhysical weathering when rocks split as
water freezes or as erosion occurs
Chemical weathering when acidic water
reacts with limestone and results in a new
substance that dissolves in water and
washes away.
Law of Conservation of Mass
Mass cannot be created or destroyed
Burning a log seems to make mass disappear
“missing” mass is actually present in the gases
that are produced as the log burns
When the log burns new substances are
formed.
EX: Iron and oxygen combining to form rust, the
masses will still be equal.