SNC1
Particle Theory of Matter
What two experiments that suggested that matter is made of particles:
a) MIXED alcohol and water result in a combined volume that is LESS
than the volumes of the original water and alcohol added together. This
suggested that
different sized particles were combined and the SMALLER particles were fitting
BETWEEN the larger particles.
b) When IRON and nitric acid are reacted together to make a new RED- coloured
substance. When this new substance was reacted with Aluminum, the IRON was
regenerated. This suggested that the particles of matter are not DESTROYED
when
chemical reactions occur.
The Particle Theory
1) All matter is made of PARTICLES.
2) Particles cannot be CREATED or DESTROYED.
3) Particles are in a constant state of MOTION.
4) The higher the temperature, the FASTER the particles move.
5) Particles are BOUND to each other by forces that tend to hold the particles
TOGETHER.
What can this theory explain?
A) Physical States of Matter: matter can be found in three states.
ACTUALLY THERE ARE FOUR STATES OF MATTER.
GASES
LIQUIDS
SOLIDS
shape:
CHANGES CONTAINER FIXED
volume:
CHANGES FIXED
FIXED
Matter can be changed from one state to another by
raising or lowering the temperature. This is done by
adding or removing energy.
Changes that require adding energy (raising temp):
MELTING
VAPORIZATION
SUBLIMATION_
Changes that require removing energy (lowering temp):
FREEZING
CONDENSATION
DEPOSITION
How does the Particle Theory Explain These States:
Particles in a:
- gas are well separated with no regular arrangement.
- liquid are close together with no regular arrangement.
- solid are tightly packed, usually in a regular pattern.
Particles in a: - gas move freely in straight lines at high speeds and only change
direction when they collide with another particle.
- liquid vibrate, move from place to place, and slide past each other.
- solid vibrate (jiggle) but generally do not move from place to place.
Liquids and solids are called condensed states because the particles are very
close together,
so the substance cannot change volume much.
Liquids and gases are called fluid states because the particles can move from
place to place, so the substance can flow and change shape.
Questions
1) When we increase the temperature of a substance to change it from a solid to
a liquid and then to a gas, what does the extra energy do to the particles?
THE EXTRA ENERGY MAKES THEM MOVE FASTER, IF THEY HAVE
ENOUGH MOVING ENERGY THEN THE BONDS HOLDING THE PARTICLES
SHIFTS (LIQUID) OR IS BROKEN (GAS).
2) Some substances must be heated to a higher temperature to make them melt
or evaporate than other Substances. What must be different about the particles
in a substance that has a higher meltingtemperature?
THE ELECTRIC BONDS BETWEEN PARTICLES ARE STRONGER.
SNC1
Pure Substances and Mixtures
All matter can be divided into two categories based on (observable) evidence.
Observations:
a) When two substances are mixed, the new substance has different properties
from the original substances.
These substances are called SOLUTIONS
Example: salt water tastes different from pure water and looks different from pure
salt.
b) In addition, the properties are variable, depending on the proportions of the
mixture.
Example: water tastes saltier and has a higher density if more salt is added to the
same amount of water.
c) Mixtures can be un-mixed (separated) by different physical processes:
i) evaporation
ii) FILTERING
iii) DISTILLATION
iv) MAGNETIC OR CHROMOTOGRAPHY
d) When mixtures are separated by physical processes into simpler
substances, one eventually produces, substances that cannot be further broken
down into simpler substances.
These new substances have physical properties that are not variable (the same
in different samples).
These types of substances are called PURE substances.
Example: salt water can be distilled (the water is evaporated off and
recondensed to a pure liquid
into water and salt. The water and salt have the same basic properties each time
you do this.
In addition, water and salt cannot be un-mixed into any other substances.
Therefore: salt and water must NOT be mixtures.
SUMMARY: all substances can be placed into one of two categories:
A) Pure Substances: properties are same from one sample to another.
cannot be separated down into other substances by mechanical means.
B) Mixtures: properties are variable from one sample to another.
can be separated into other substances by mechanical means.
Given that samples of pure substances always have the same properties, where
as mixtures have variable properties (density, viscosity...) suggests an
explanation based on the particle theory of matter.
3) How might the theory explain this? MIXTURES ARE COMBINATIONS OF
DIFFERENT PARTICLES WHICH CAN BE SEPARATED INTO PARTICLES OF
THE SAME TYPE. PURE SUBSTANCES WILL BE COMPOSED OF ONLY
ONE PARTICLE AND THUS WILL ALWAYS HAVE THE SAME PROPERTIES.
4) Classify the following substance into pure substances (PS) or mixtures (M).
a) Air
MIXTURE
b) Oxygen
PURE
c) Sugar
PURE
d) chocolate chip cookies MIXTURE
e) sugar water
MIXTURE
f) syrup
MIXTURE
g) water
PURE
h) aluminum foil
PURE
i) copper wire
PURE
j) dusty air
MIXTURE
j) wet sand
MIXTURE
k) muddy water
MIXTURE
How does Particle Theory of Matter explain the difference between mixtures
and pure substances?
1) Observation
Pure substances: SAME properties; cannot be separated into other substances.
Mixtures: VARIABLE properties, can be separated into other substances.
Explanation
Pure Substance: only one type of particle is present.
- the properties must be consistent because the same type of particle is present
in each case
- the substances cannot be physically separated because any particles that are
removed are the
same as the ones that are left behind.
Mixture: at least two types of particles are present.
- the different particles can be in any ratio, so the properties of the mixture are
variable.
- the substances can be physically separated because the different particle types
can be
separated from each other.
(one particle type may evaporate at a lower temperature, for example)
5) Which of the following substances are mixtures and which are mixtures?
A) PURE B) PURE C) MIXTURES D) MIXTURE E) PURE
6) Which two substances would have to be mixed to get substance D? A & E
7) a) If substances C and D were to be separated, would you get the same pure
substances? YES, JUST DIFFERENT AMOUNTS
b) What is different about substances C and D? AT LEAST 2 TYPES OF
PARTICLES
8) a) What is different about the particles in substance B compared to the other 4
substances? EACH PARTICLE IS MADE UP OF OTHER PARTICLES BONDED
TOGETHER IN THE SAME RATIO.
b) Why is substance B a pure substance?
SUBSTANCE B IS A PURE SUBSTANCE BECAUSE IT IS MADE UP OF ONE
TYPE OF PARTICLE WHICH WILL HAVE ITS UNIQUE PROPERTIES.