Transcript MIXTURES

MATTER: matter can be classified
into mixtures, solutions,
elements and compounds.
Matter that consists of 2 or more substances that are
NOT chemically combined.
They are Physically Combined
They keep their own properties.
They can change physically.
Any amount of each substance is ok.
Most mixtures can be separated physically by:
magnets, evaporation, filtration, or centrifuge,
and distillation.
TYPES OF MIXTURES
HETEROGENEOUS:
• Not well mixed; Does not appear the same
throughout.
• Will separate upon standing.
• Particles are large, and can be seen.
• Ex: concrete, oil and vinegar; cereal and bananas;
salad, BLT; PB&J
HOMOGENEOUS
• Two or more substances evenly mixed.
• You can NOT see the different substances, even
with a microscope!
• Examples: gatorade, salt water, brass, air
Heterogeneous mixtures
A type of mixture where two or more substances are not evenly
mixed. You can see with your eyes the different parts that make
up the mixture.
•The particles are insoluble. This means
the particles do NOT dissolve.
•Only scatter throughout when shaken.
•*Often cloudy
• Scatter light(Tyndall Effect)
Mixture that is EVENLY mixed.
• Appears the same throughout
• Particles are very small , and sometimes dissolved.
Also known as Solutions — have 2 parts to them:
solute and solvent
Solute—substance that dissolves (ex. Salt, sugar)
Solvent—substance that does the dissolving
(Water is called the Universal solvent!)
o Particles are dissolved in a solution.
o Solutions do Not scatter light
o They often appear clear
o 1 substance dissolves in another.
( ex: water)
Solute and solvent
Key terms about solutions:
• Soluble: a substance can dissolve in another substance
(salt)
•
•
Insoluble: Substance can NOT dissolve in another
substance (pepper, oil)
Solubility: Amt. of solute that can completely
dissolve in a specific amt. of solvent at a given
temperature. (Salt water)
• Saturated: all the solute that can be dissolved in a
specific amt of solvent at a given temp. – can’t absorb any
more.
Alloy: Metal solutions that are Solids dissolved in solids—
Brass: copper and Zinc
Gold: gold and copper
The tyndall effect
EXAMPLES OF COLLOIDS:
Fog= liquid in gas
Butter= liquid in solid
Smoke=liquid in gas
Mayo= liquid in liquid
HOW ARE ELEMENTS DIFFERENT
FROM MIXTURES?
When all particles are alike, it is a
pure substance.
Elements- simplest pure substance;
there are MORE THAN 113 elements; they
Began to be discovered in the 1940’s.
Atom- smallest particle of an element that
has all the properties of that element.
SO WHAT ARE COMPOUNDS AND
MOLECULES, THEN?
Compound- 2 or more different elements
chemically combined
ex. H2O, NaCl
Molecules- 2 or more atoms chemically
combined.
ex. H2, H2O, N2
Elements
Compounds
Mixtures
Made up of only 1 Made up of more Made up of more
kind of atom.
than 1 kind of
than 1 kind of
atom.
molecule.
Can’t be broken Can be broken
Can be separated
down by chemical down by
by physical
means.
chemical means. means.
Have same
properties as
atoms making it
up.
Have different
properties from
elements making
it up.
Have same
properties as
substances
making them up.
Have same
properties
throughout.
Have same
properties
throughout.
Have different
properties
throughout.
Chemical Symbols- shorthand way to represent
elements.
ex. C, H, Na (sodium) Ca, Cl
Chemical Formula- combinations of chemical
symbols
ex. H2O
Subscript- tells the number of atoms in a
compound ex. H2O CO2
Coefficient- tells the number of molecules
ex. 2H2O
Chemical Equation- describes the chemical
reaction using symbols and formulas
WHAT IS INSIDE AN ATOM????
STRUCTURE OF AN ATOM !!!!!
THE PLAYERS:
• 3 major subatomic particles:
• Proton- positively charged, 1 AMU, inside the
nucleus, determines the element
• Neutron- no charge, 1 AMU, inside the
nucleus.
• Electron-negatively charged, 1/1836 AMU ,
outside the nucleus on energy shells and
energy levels.
• AMU= ATOMIC MASS UNIT– (THEIR MASS!!)
HOW DO WE WORK WITH ATOMS AND
ELEMENTS?????
• Atomic #--# of protons of an element. It identifies
the element.
• A#= #P
• Mass # - This is the # that is = to the # of protons
and the neutrons in the nucleus.
• m# = P + N
• NEUTRAL ATOM: # E = # P
• Atomic Mass (weight) -- the average mass # of all
of the isotopes of an element
BUT WHAT IS THE NUMBER
UNDERNEATH THEM ON THE PERIODIC
TABLE???
Isotopes—These are when an element has its
regular # of protons, but a different # of
neutrons. Isotopes of an element are that
element, with a different # of neutrons.
• ex: H-3, U-238.