Transcript Matter_ properties_ mixtures and separation methods 2012

MATTER
What it is all about
Chemistry – Matter Unit
• What is matter?
• What is the
organization of
matter?
• What is the
nature of matter?
MATTER
Can the matter be separated by physical
means?
Mixtures
Pure Substances
Constant composition
Heterogeneous
Homogeneous
Separation by chemical means
Compounds
Elements
Matter
Matter is anything that occupies space and has mass.
The particle theory of matter.
The particle theory states that…

all matter is made from particles

different particles have different properties

particles are constantly in motion
States of Matter
A solid has a definite shape and volume.
A liquid has a definite volume but no definite shape.
A gas has neither a definite volume or shape.
Gas
Liquid
Solid
SOLIDS
• the attraction between particles is strong so the
matter holds its shape. The particles are still moving,
but they are not able to slide past each other
LIQUIDS
• the attractive forces are not as strong. The particles
are able to move past each other and slide around
GAS
• the attraction between particles is so weak that they
fly in every direction filling the container that they are
held
solidification (freezing)
melting
Properties of Matter
Physical Properties:
• a quality or condition of a substance that can be
observed or measured without changing the
substance’s composition
Examples: color, texture, boiling point, density,
mass etc…
Chemical properties
• Properties that do change the chemical nature of matter
•
Properties the matter exhibits when chemical change occurs
Ex. oxidation, flammability, corrosiveness, acidity
Physical Properties Subcategories
• Extensive Properties depend upon the amount
of matter that is present.
Ex. Length, mass, volume, heat …etc
• Intensive Properties do not depend on the
amount of matter present. These properties are
the same for a given substance regardless of
how much of the substance is present.
Ex. Color, density, melting point, ductility, temp… etc
Examples of physical properties
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Boiling point
Specific gravity (at constant temperature)
Viscosity (at constant pressure and temp.)
Freezing point
Solubility in water (hot/cold)
Density
Melting point
Mass
Volume
Specific heat capacity
Heat
Temperature
Ductility/Malleability
Density
• the mass of a substance per a specific
amount of volume
Density = mass
volume
• The mass and volume are directly
proportional. If one increases the other
increases
Physical and chemical change
• Physical change
– the altering of the physical form but not
composition of matter
– ex. Pounding, pulling, changes of state
• Knowledge of physical change leads to…
– the understanding of separation of mixtures
– ex. Distillation, crystallization, chromatography, filtration
Chemical change
• Chemical change
– change in which the matter is converted into
matter with different composition and
properties
Indicators of chemical change
1. heat and/or light energy
– Energy changes within the system
2. Production of gas
- release of gas from the system
3. Formation of a precipitate
- when two (or more) solutions are put
together an insoluble solid is produced
4. Color change
- the system changes color
- not always an indicator of chemical
change (can be physical
MATTER
Can the matter be separated by physical
means?
Mixtures
Pure Substances
Constant composition
Heterogeneous
Homogeneous
Separation by chemical means
Compounds
Elements
Pure Substances
• Fixed composition
• Cannot be separated into simpler
substances by physical methods (physical
changes)
• Can only be changed in identity and
properties by chemical methods
• Properties do not vary
Pure Substances
Compounds
• Can be decomposed
into simpler
substances by
chemical changes,
always in a definite
ratio
Elements
• Cannot be
decomposed into
simpler substances
by chemical changes
MIXTURES
mixture:
- combination of two or more kinds of
matter each of which retains its own
composition and properties
- physical blend of two or more substances
More of Mixtures:
heterogeneous mixture:
- a mixture containing substances that are not
evenly distributed
- different from point to point
ex. granite ---> quartz, feldspar, and mica
Phase
• mixtures that are obviously heterogeneous and have
separate, distinct parts
Ex. Oil forming layers in water is another
Interface – the region where two or more phases meet
MoM
homogeneous mixture
- a mixture containing substances that are uniformly
distributed with the particles blended completely
- composition and properties are uniform throughout
- also called solutions (mixed on a scale of individual
particles) ex. I molar copper II sulfate
• To the eye, the mixture appears to be pure
substance.
Solutions
(Homogeneous Mixtures)
Can you tell the difference?
Parts of a Solution
• SOLUTE – the part of
a solution that is being
dissolved (usually the
lesser amount)
• SOLVENT – the part
of a solution that
dissolves the solute
(usually the greater
amount)
• Solute + Solvent =
Solution
Solute
Solvent
Example
solid
solid
Brass: Copper and Zinc
solid
liquid
Seawater: NaCL in
water
gas
solid
Moth balls: naphthalene
liquid
liquid
Ethyl alcohol and water
(miscible)
gas
liquid
SODA: CO2 gas in
water
gas
gas
AIR: O2 gas, N2 gas
Some other terms to know!
• Solubility
– amount of substance that dissolves in a given
quantity of solvent at specified conditions
• Soluble
– The ability to be dissolved
• Miscible
– Liquids that are able to dissolve in other liquids
• Immiscible
– Liquids that are insoluble in another liquid
Somewhere In Between
• Some mixtures are in-between heterogeneous
mixtures and homogeneous solutions.
• suspension
• particles settle out upon standing
• differ from a solution due to particle size being much greater (> 100
nm to 1 nm).
• filtration to separate
• colloid
• smaller particle size than suspension but not as small as true
solution
• the particles are so small that they pass through most filters
• fog is an example of a colloid
• the Tyndall affect is exhibited
https://www.youtube.com/watch?v=bn1-Zgcpp_4
Define the following words
solubility.
Miscible
Immiscible
Definitions
Solutions can be classified as
saturated or unsaturated.
A saturated solution contains the
maximum quantity of solute
that dissolves at that
temperature.
An unsaturated solution contains
less than the maximum
amount of solute that can
dissolve at a particular
temperature
Definitions
SUPERSATURATED SOLUTIONS contain more solute
than is possible to be dissolved in a given amount of
solvent
Supersaturated solutions are unstable.
-- the supersaturation is only temporary
-- need to warm the solvent so that it will dissolve
more
-- then need to cool the solution slowly
http://www.youtube.com/watch?v=jVhPZg3dxIg
http://www.youtube.com/watch?v=HnSg2cl09PI&feature=related
Separation of Mixtures
types of…
• Filtration
– Separation of mixture on the basis of
differences in the size of the particles
– Mostly used to separate solids from liquids
(but
filtration is used to separate all phases of matter from one another)
Ex. Air filters separate gas (air) from solid (dirt particles)
http://www.youtube.com/watch?v=nJVbFIIycKo
https://www.youtube.com/watch?v=lfGYd1wrTgE
• Distillation
– Based on the tendency of a substance to
vaporize (turn to a gas)
– Based on boiling point differences
– The substance in the mixture with the lowest
boiling point will vaporize first from the mixture
Ex. Crude oil  http://www.youtube.com/watch?v=26AN1LfbUPc
https://www.youtube.com/watch?v=JZdvsQzOKuk
• Chromatography
– Based on the differences in solubility
– Two types  Gas and Paper
– Mixture separates as it travels (most soluble
separates first)
Solute – substance that gets dissolved
Solvent – substance that does the dissolving
http://www.youtube.com/watc
h?v=LY44uD2miYM
Ex. Separating ink in a marker
http://www.youtube.com/watch?v=OKxRx0ctrl0&feature
=related
• Crystallization
– Separation of the mixture is based on
solubility differences
– Temperature changes within the mixtures
change solubility of parts of the mixture
Solubility – the amount of a solute that is able to
dissolve in a given amount of solvent
Ex. Rock candy
http://www.youtube.com/watch?v=l_USYub3djY&feature=related
SOLUTION CHEMISTRY
Concentration:
• amount of solute in a given amount of solvent (can be
determined quantitatively)
Dilute:
• a solution with a small amount of solute per solvent
amount (relative term)
Concentrated:
• a solution with a large amount of solute per solvent
amount (relative term)
BOTH DILUTE AND CONCENTRATED ARE QUALITATIVE
Concentration of Solute
The amount of solute in a solution is
given by its concentration.
Molarity
(M)
=
moles solute
liters of solution
The concentration of a solution is said to be its molarity.
Ex. 1 M CuSO4
“1 molar copper II sulfate