CHEMISTRY

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CHEMISTRY

• The good news and the bad news

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Its all aboutbuilding blocks
CHEMISTRY
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COMPOUNDS
Hydrogen
Compounds are two or more elements that share
electrons or have taken or given electrons away.
Carbon-6
Hydrogen
Hydrogen
Hydrogen
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Atoms combine to form compounds in simple ratios,
such as 11, 12, 22, 13, and so forth.
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Chemical Equations are simple.
2H2 O2 ? 2H2O
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Ba(OH)2.8H2O(s ) 2 NH4SCN(s ) --gt Ba(SCN)2(s )
10 H2O(l ) 2 NH3(g )
O
Ba
O
O
Ca
S
O
O
H
H
O
Ba(OH)2(aq) CaSO4(aq) ? BaSO4(s) Ca(OH)2(aq)
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Good news Your car rolled off the pier but
didnt fall into the water.
Bad news The damage to the yacht is more than
the value of the car.
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Bad News 1
ATOMS ARE TOO SMALL TO COUNT
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Imagine counting grains of sand. Not easy but
not impossible. Now imagine trying to count
grains of sand that are 2,000 miles away. Quite
impossible even with the worlds best telescope.
Well this is the challenge in counting atoms.
Counting atoms from 1 foot away is the same as
counting grains of sand 2,000 miles away.
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Bad News 2
COUNTING ENOUGH ATOMS IS IMPOSSIBLE
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Chemical Equations are simple.
2H2 O2 ? 2H2O
Chemical equations are quite easy. Here we count
out 4 hydrogens and 2 oxygen atoms and we can
make two water molecules. But how many hydrogens
and oxygens would we count out to make enough
water to fill a one liter bottle of water?
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Imagine the number of grains of sand in a handful
of sand thousands or maybe a million? It
would be difficult to count that many. Now
imagine the number of grains of sand that would
be present if we covered all of the Earth (land
and sea) 10 miles deep of sand. That number of
grains of sands is the same number of water
molecules needed to fill a 1 liter bottle.
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Art of Counting Without Counting
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COUNTING COINS WITHOUT COUNTING
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Periodic Table of the Elements
The numbers under the element names are the
relative weights. However, if you consider one
mole of the element (6 x 1023 atoms) then these
numbers are read as grams.
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Bridge between mass and number
MOLE
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VOLUME
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COUNTING ATOMS IN GASES
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Gas Volume
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PRESSURE
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TEMPERATURE
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Art of Counting Without Counting
MASS
VOLUME
PRESSURE
TEMPERATURE