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Lecture 17

• help

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Bio
Katherine Switzer
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• The woman's escorts, Coach Arnold Briggs and her
  shot-putter boyfriend, Tom Miller

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"That accomplishment changed my life and gave me
a tremendous sense that there was nothing in the
world I couldn't do," Ms. Switzer recently told
the Baltimore Sun.
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• Daughter -
• Defender

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homework

• Do problems 1 11 on page 113

Hand in Experiment 3 magnesium oxidation lab
And extra credit for honors students (general
extra credit is on its way)
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Check homework and review homework
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Last time we talked about the atomic mass and the
molar mass

• What is the difference between
• atomic mass
• Molar mass

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What is the mass of one atom of Carbon use units

• What is the mass of one mole of xenon use units
• What is the mass of two moles of CO use units
• What is the mass of two atoms of H2O use units

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Mass a penny and determine how many atoms are in
the

• Mass a mouth full of water and determine how many
  atoms of H2O are present
• Have a student write their name on the board with
  CaCO3 chalk and determine how many atoms are on
  the board

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Email lab sheet

• This is due next class!!!!!!!!

The magnesium must be coiled about the size of a
dime do not let it be so expansive that it sits
off the bottom of the crucible
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Lecture 12
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Biography on Jan Baptista van Helmont

• Lived from 1577 until December, 1644

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Urged on by a desire to relieve human suffering,
he began to study medicine.

• He contracted scabies and was treated
  unsuccessfully by doctors

He went all over looking for a cure and finally a
herbologist cured him and took him on as a student
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His entire family contracted scabies and died,
he tried everything he had learned but could not
cure them
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This horrible event in his life did not defeat
him it empowered him!!!!
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He then made it his mission to understand these
herbs and chemicals as a chemist

• Studied
• CO2 Gunpowder acids
• "Van Helmont was wholly taken up in chemical
  operations night and day.... he was scarcely
  known in his neighborhood....
  nor scarce ever still out of doors."

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Father of biochemistry
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5 lbs to 164 lbs only given water
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The labs are due today by Email
Turn in pages 113 problems
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homework

• Both pages
• Read pages 116 to 122
• problems on page 122 9-14
• Read pages 124 to 130
• problems on page 131 1-9

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Access OG 12
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Elements come together to gain stabilization

• MgO
• NaCl
• SiO2
• Gold
• Carbon

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Gold nugget
Why isn't this a crystal
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• rusting

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Rusting is the process where a metal is joined to
a oxygen
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Metals are Oxygen is

• Rusting is the process where metal and oxygen are
  bound.

Metals lose electrons and oxygen gains electrons
and the resulting ions combine as magnets
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All metal rusts

• Nearly all metals once the outer layer becomes
  oxidized (rusted) it can no longer oxidize any
  further

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Metals such as bronze, copper, brass, steel and
lead naturally tarnish and corrode. When they
corrode on the outside they typically turn
colorcopper turns greensteel brown brass
reddishaluminum whiteish
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Like I mentioned last class, Iron is the only
metal that once it oxidizes the iron oxide
created will flake and new metal oxidizes
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Heat it up and it will oxidize (rust) fast
In our lab we used the metal Mg2
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ELECTRONS ARE THE CURRNCY OF MATTER
FOLLOW THE MONEY
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The heat opens the metal-metal bonds and opens
the O2
Mg2

• The magnesium will actually gain mass as it bonds
  to oxygen and become magnesium oxide
• MgO

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An atom of Mg has a mass of 24.3 amuan atom of
oxygen has a mass 16 amu

• The Magnesium will almost double the weight

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As Helmonts tree gained Carbon from CO2 , the
metal will gain weight by drawing in Oxygen
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Can we tell by looking at the periodic table
which elements will throw off electrons and which
elements will be suck them in?
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• Let us begin by discussion the Periodic table

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We have discussed how the periodic table is laid
out in reference to electron placement
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A vertical column is called a groupas you move
up and down a group all the elements have the
same number of valance electrons so all elements
in a group have similar properties.
Groups have things in common
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A horizontal row is called a periodas you move
from left to right the number of valance
electrons increase until you reach 8. The
properties of the elements are different but they
all have a similar energy level
Periods have little in common
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Main Group Elements are predictable because the
valance electrons are predictable
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The main group elements are categorized as
Alkali metalsAlkaline earth metalsHalogensNobe
l gases
Note they are in alphabetical order
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Alkali metals
Group one they want to lose one electron so very
reactive usually stored in oil
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Alkaline Earth metals

• Less reactive than Alkali metals but still very
  reactive (its harder to lose 2 electrons)

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Halogens
Most reactive nonmetal. Want to gain one
electron Reacts quickly with Alkali metals
because they want to give up one electron and
halogens want one
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Nobel gases

• Full set of electrons and thus not reactive

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Transition metalsalso called d block metals
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Transition metals do not have a distinct
electronic configuration

• The interesting thing about transition metals is
  that their valence electrons are present in more
  than one shell. This is the reason why one
  element will often will give up one, two, or
  three electrons.

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Lanthanides Series f4th shellActinides Series
f5th shelloften called F orbital metals
The lanthanides are all very reactive and
electropositive. The chemistry is dominated by
the 3 oxidation state. Despite the high charge,
the large size of the ions results in low charge
densities and their compounds are ionic in
character.
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Metals

• Excess electrons enable elements that are metals
  to
• a) shine brightly
• b) malleable bendable
• c) conduct electricity well
• d) Ductile stretched into a wire
• e) conduct heat well

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Metals are like tapioca pudding
Metallic bonding
Create a magnet
Nucleus in a sea of electrons
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Sea of displaced electrons
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alloy

• Is a mixture of the different atoms of different
  metals

Properties of each of the different metals come
together to yield an alloy
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Some alloys are substitution alloys
The alloy has a combination of the alloyed
metals gold and silver giving white gold that is
a little harder
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Some alloys are interstitial alloys
the added atoms are much smaller than the atoms
in the network, like the carbon atoms added to
iron to make steel, they can fit into the holes
between the layers of atoms in the network.
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Pure vs Alloy
Alloy Iron and Carbon
Iron Fe
The addition of .5 to 1.5 carbon gives the iron
the brittleness of carbon but the strength of
iron resulting in the production of steel
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If you cool carbon iron (steel) slow anneal the
carbon moves away from the iron as the iron
establishes long grains and pockets of carbon
Soft malleable steel
Depending on how fast you cool the steel the more
or less grain boundaries you get
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Annealing is heating the metal and than slow
cool to produce grain boundaries and thus soften
the metal
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• The grain boundaries act like roots in dirt and
  offer malleability (flexibility) and softness
  because of the voids at the grain boundary
  interfaces

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If the steel is cooled fast fewer grains are
established and the iron carbon crystals
predominate. Like a true crystal the steel is
hard and brittle like crystal steel
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The process of quenching, preserves the crystal
structure of steel by suddenly cooling it into a
much harder and brittle material before the
grains can develop
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Do the mettle of metal lab

• Bobby pins and bending

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Nonmetals

• Nonmetals are those elements that suck in
  electrons rather than give the electrons up

Why is H considered a nonmetal and metal?
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Nonmetals are

• Brittle
• hazy in color and lack luster
• Do not carry a electric current
• Do not carry heat very well
• Carry a charge
• Very reactive with alkali metals and alkaline
  earth metals

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Metalloids or semiconductors

• Part metal part nonmetal