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Bridge Project Winners
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Bridge Homework
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Web site/Newsgroup
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Reading for this week
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Vocabulary
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Acids, acidity, bases,
basicity, pH, indicators, corrosive, ions, salts,
hydroxide, Salts
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Baseball
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Why?
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Who Plays
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Rules
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Questions
The fact that water
dissociates to form H+ and OH- ions in a
reversible reaction is the basis for an operational definition of
acids and bases that is more powerful than the definitions proposed
by Arrhenius. In an operational sense, an acid is any
substance that increases the concentration of the H+ ion
when it dissolves in water. A base is any substance that
increases the concentration of the OH- ion when it
dissolves in water.
These definitions tie the
theory of acids and bases to a simple laboratory test for acids and
bases. To decide whether a compound is an acid or a base we dissolve
it in water and test the solution to see whether the H+
or OH- ion concentration has increased.
How would you know if it's aN ACID
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some metal hydrides
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HI, LiH, NaH, KH, MgH2, Cao
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some metal oxides
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Li2O, Na2O, K2O, MgO, CaO
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some metal hydroxides
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LiOH, NAOH, KOH, CA(OH)2, Ba(OH)2
How would you know if it's a BASE
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some non-metal hydrides
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HF, HCl, HBr, HCN,HSCN, H2S
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some non-metal oxides
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CO2, SO3, SO2, NO2,NO2,P4O10
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non-metal hydroxides
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HOCl, HONO2, O2S(OH)2, OP(OH)3
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Try it on the lab exercise
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Common Name |
Scientific
Name |
Formula |
metal |
non-metal |
hydride |
oxide |
hydroxide |
Acid or Base |
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a.vinegar |
Acetic Acid |
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N |
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b. sugar
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Glucose |
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c. ammonia e.
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Ammonia |
NH4OH |
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d. Sode |
Carbonic Acid |
H2CO3 |
N |
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e.
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sodium
hydroxide |
NaOH
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Y |
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f.
Water |
Agua |
H2O
or HOH |
N |
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g. Breath |
Carbon Dioxide |
CO2 |
N |
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h. Milk |
Calcium
Carbonate |
CaCO3,
Ca(OH)2 |
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The pH Scale
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7 is pH of pure water
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> 7 greater basicity
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<7 greater acidity
Acid and Bases Challenge
Harry celebrated a little too much on New Years Eve last year and
woke up with a very upset stomach. He had committed to go to his
mother-in-laws with his wife to watch football and have dinner.
When he got there he was obviously not feeling well. He got all
sorts of advice from friends and family about how to ‘cure’ his
problem. The only ones that he had available at that time were:
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Milk
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Menudo
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Alka-Seltzer
(soda water)
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Plain Water
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Orange Juice
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Flat Beer
CAN YOU HELP HARRY DECIDE?
Assume that his problem is that his stomach has become too acidic.
To
make him feel better it must be made more neutral. Which subtance
does this best?
Use
slightly diluted vinegar to model his stomache fluids
There is plenty of Red Cabbage there
Design an experiment that could tell Harry which one of the 6
‘cures’ above would be the best for his problem.
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