Section 2, Unit 2
Mixtures and Separation Techniques
Separating These Mixtures
– Separation Techniques target the components’
differences in physical properties.
• Review: What are Physical Properties?
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FiltrationEvaporationChromatographyDistillationCentrifugation –
Pure or Impure
• Chemists Classify Matter As Pure or Impure
– Pure – If the material consists of only a single
element or a single compound
– Impure – If the mixture contains two or more
elements or compounds
Pure or Impure
• Flow Chart
Pure or Impure
• Mixtures can be either
Homogeneous
or
Heterogeneous
Heterogeneous Mixture
• Heterogeneous Mixture – The different components
can be seen as individual substances
Examples
–“Snow” in a snow globe
–Pizza
–Pulp in Orange Juice
–Any Others??
Homogeneous Mixture
• Homogeneous Mixture – Has the same composition
throughout. You can take multiple samples from
different locations and the compositions will be the
exact same.
Examples:
• Air
• Seawater
• Kool-Aid
Separation
• How can you separate these solutions??
– Milk (proteins are suspended in solution)
– Blood (cells and proteins are suspended in solution)
– ___________________
» Yields two layers (solution on top, suspensions on
bottom)
Atoms are the Fundamental
Components of Elements
– The Periodic Table contains a relatively small
number of atoms that form an unlimited number
of different materials.
• This is based on how they combine or bond together
Atoms are the Fundamental
Components of Elements
– The Periodic Table contains a relatively small number
of atoms that form an unlimited number of different
materials.
• This is based on how they combine or bond together
– Element – Any material consisting of only one type of
atom.
– Atom – Submicroscopic particles in a sample. Each
element is designated by a symbol (Atomic Symbol)
• Co =/= CO, only the first letter is capital
Atoms are the Fundamental
Components of Elements
– Elemental Formula – How many atoms are
bonded together in an element
• Au = Gold
ii. N2 = Nitrogen
iii. Ni = Nickel
– Seven Diatomic Elements:
–Oxygen, Hydrogen, Nitrogen, Bromine,
Chlorine, Iodine, Fluorine
– How about diatomic oxygen vs. ozone, O3?
–Are they the same?
–No, BUT both are elemental forms of oxygen
Combining Elements to Form
Compounds
– Molecule- Consists of two or more atoms
combined in a definite ratio
– Compound– Atoms of different elements bound
to one another
– We had an Elemental Formula for elements, how
will we represent chemicals bound together to
form chemical compounds?
Combining Elements to Form
Compounds
– Chemical Formula – How much of what is in the
compound (symbols and subscripts)
• NaCl: One sodium per chlorine atom
• MgCl2: One magnesium per two chlorine atoms
Combining Elements to Form
Compounds
– Hydrogen Sulfide is one of the smelliest
compounds. Rotten eggs get their characteristic
bad smell from the hydrogen sulfide that they
release. Can you infer from this information that
elemental sulfur is just as smelly?
– *Compounds have Physical and Chemical
properties that are different from the properties
of their elemental compounds
• “Separation
Techniques” lab
tomorrow – dress
appropriately.