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The Chemistry of The Chemistry of Acids and BasesAcids and BasesThe Chemistry of The Chemistry of Acids and BasesAcids and Bases
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Acid and Base ScaleAcids pH from 0 to 7Neutral pH is 7 Base pH from 7 to 14
pH is a measure of hydrogen ion concentrationpH = -log[H+]
33AcidsHave a sour taste.
Vinegar, orange juice, lemonade.
Donates an H+
Have a bitter taste.
Feel slippery.
Donates OH-
Ammonia, detergents, bleach
Bases
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Monoprotic vs. Diprotic
Monoprotic- an acid that can donate only 1 proton to a base (HCl)
Diprotic- an acid that has two ionizable hydrogen atoms in each molecule, such as sulfuric acid (H2SO4)
Effects titrations
55ACID-BASE REACTIONSACID-BASE REACTIONS
TitrationsTitrationsACID-BASE REACTIONSACID-BASE REACTIONS
TitrationsTitrations
What is a titration? What is a titration?
HH22CC22OO4(q)4(q) + 2NaOH + 2NaOH(aq)(aq) Na Na22CC22OO4(aq)4(aq) + 2H + 2H22OO(l)(l)
acidacid basebase Ionic SaltIonic Salt WaterWater
Oxalic acid,
H2C2O4
A common laboratory method of chemistry that is used to determine the unknown concentration of an identified acid or base
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HCl(aq) + NaOH(aq) HOH(l) +NaCl(aq)
•When we add the two together what do we get?
–Neutralization Reaction
•What is the equivalence point?
–Equal moles of acid and base
Acid + Base
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Titration1. 1. Add known solution to Add known solution to
unknown solution to unknown solution to determine concentration.determine concentration.
2. Phenolphthalein indicator 2. Phenolphthalein indicator shows the equivalence shows the equivalence point. (Acid = Base)point. (Acid = Base)
This is called This is called NEUTRALIZATION.NEUTRALIZATION.
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35.62 mL of NaOH is neutralized with 25.2 mL of 35.62 mL of NaOH is neutralized with 25.2 mL of
0.0998 M HCl by titration to an equivalence point. 0.0998 M HCl by titration to an equivalence point.
What is the concentration of the NaOH?What is the concentration of the NaOH?
Ma Va = Mb Vb
Ma Va = Mb Vb
(0.0998 M) (25.2 mL) = 0.0706 M
(35.62 mL)
Standardization of a solution of NaOH Standardization of a solution of NaOH Standardization of a solution of NaOH Standardization of a solution of NaOH
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Practice
a. 35.0b. 1.12c. 25.8d. 62.4e. 39.3
In a titration of 35.00 mL of 0.737 M H2SO4,
__________ mL of a 0.827 M KOH solution is required for neutralization.
In a titration of 35.00 mL of 0.737 M H2SO4,
__________ mL of a 0.827 M KOH solution is required for neutralization.
1010
RemindersHomework:
•Titrations WS
•Read through lab
Reminders:•Parent Letter DUE – bring in ASAP
•Extra Credit Due Friday (5/11)
•Thermo Test Corrections Due Thursday (5/10) at 8:30 am
•Sig Figs Redemption Thursday (5/10) at 7:30 am
1111
Wednesday and ThursdayMay 9 and 10
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Review Homework
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Review Homework
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What is too pink?
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The Stopcock
ClosedOpen
1616The Meniscus
• Read “upside down”
• Use paper to help see line
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More Hints• Label beakers (tape on
hood)
• Use paper to see color change
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Acid or Base and Skin
Severity will vary with concentration, but
BE SAFE, NOT SORRY!!
Rinse skin IMMEDIATELY and call for Ms. Bjorge
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Standardization of a Base Lab
Wear goggles and aprons
If I have to tell you once to put them on you are out with a ZERO!
Leave Buret in holder
You will have to do multiple trials (as many as 10)
Lab “write up” due BEGINNING of the period on Friday
2020Done in lab?
Did you complete at least 3 GOOD trials?
The more the merrier!
Homework:
Lab Write Up
Study for quiz
Reminders:Parent Letter DUE – bring in ASAP
Extra Credit Due Friday (5/11)
Thermo Test Corrections Due Thursday (5/10) at 8:30 am
Sig Figs Redemption Thursday (5/10) at 7:30 am
Acid/Base Quiz Friday (5/11)
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