Name:_____________________________________________________________Period:_____Date:________
I. Definitions:
1. Arrhenius (1887)•
________________produce ________________in aqueous solutions
•
_________________produce ______________in aqueous solutions
_________________, so only allows for aqueous solutions
only protic acids (acids that donate a proton(s)) are allowed; required to produce
hydrogen ions
only hydroxide bases are allowed
2. Bronsted-Lowry (1923)
Johannes Brønsted
(1879-1947)
Denmark
•
___________________are _____________________________
•
___________________are _____________________________
Thomas Lowry
(1874-1936)
England
aqueous solutions are permissible
bases besides hydroxides are permissible
only protic acids allowed
3. Lewis (1923)
•
__________________________ are _________________________
•
___________________________are _________________________
least restrictive of acid-base definitions
Ex:
Lewis
Base
Lewis
Acid
Ex:
Lewis
Acid
Lewis
Base
1
II. Properties of Acids:
1. taste ____________
2. changes litmus (a blue vegetable dye) from _________________________
3. their aqueous (water) solutions conduct electric current- ____________________________
4. react with ______________to form _______________________________
5. evolve _______________________________upon reaction with an active metal (such as alkali
metals, alkaline earth metals, Zn, Al)
III. Properties of Bases:
1. taste _____________________
2. feel ____________________________________________
3. Turns __________ litmus ______________
4. their aqueous (water) solutions conduct electric current – electrolytes
5. react with ___________________to form _________________________________
IV. Examples of Common Acids & Bases:
_______________
__________
Citric acid (notably citrus fruits)
Detergents
Ascorbic acid (vitamin C)
Soap
Vinegar (5% acetic acid)
Lye (NaOH)
Carbonic acid (for carbonation of soft drinks)
Household ammonia
(aqueous)
Lactic acid (in buttermilk)
V. What makes a strong acid or strong base?:
1) STRONG electrolytes are _________________dissociated into ________ in ___________
•
__________________ = a solution that conducts electricity ( Ex: acids, bases, salts)
2) The acid or base molecule does not exist in aqueous solution, only___________!
3) WEAK electrolytes are ____________________ dissociated.
A. Strong Acids:
•
•
________________dissociate in water, forming ________ and an anion
100% dissociation isn't true as solutions become more concentrated. If the acid is 100%
dissociated in solutions of 1.0 M or less, it is called strong.
2
•
•
6 strong acids:
HCl - hydrochloric acid
HNO3 - nitric acid
H2SO4 - sulfuric acid
HBr - hydrobromic acid
HI - hydroiodic acid
HClO4 - perchloric acid
Common acids and their formulas: (YOU NEED TO KNOW THESE!)
Hydrochloric Acid = HCl
Nitric Acid = HNO3
Sulfuric Acid = H2SO4
Carbonic Acid = H2CO3
Phosphoric Acid = H3PO4
Acetic Acid = CH3COOH
B. Weak Acids:
•
Only __________________ dissociates in water to give H+ and the anion.
•
Ex: hydrofluoric acid, HF, and acetic acid
C. Strong Bases:
•
Dissociate ___________ into the cation and __________ (hydroxide ion).
•
The hydroxides of the ______________ and _______________ metals usually are considered
to be strong bases.
D. Weak Bases:
•
Ex: ammonia, NH3
•
Most weak bases are ______________of weak acids.
•
Weak bases ________________ furnish OH- ions by dissociation.
•
Instead, they react with _____________to generate OH- ions.
E. pH:
•
________ = a measurement of the concentration of hydrogen ions in a solution.
•
Because of its mathematical formulation, ________________values are associated with
solutions with _____________________________of hydrogen ions
•
And __________________values occur for solutions with ____________________ of
hydrogen ions.
•
pH scale: ranges from _________ to measure how acidic or basic a substance is
•
a pH of ____ indicates a _____________________ substance
0
ACID
7
N
E
U
T
R
A
L
14
BASE
3
VI. Indicators:
1) What is an acid-base indicator?
•
it is a ______________or a __________________
•
it does not change color from pure acid to pure alkaline at specific hydrogen ion concentrations
•
color change occurs over a __________________of hydrogen ion concentrations
2) Examples of indicators:
• Bromthymol blue
• phenol red
• phenolphthalein
• litmus
• pH paper
3) Why measure pH?
•
•
Everyday solutions we use - everything from____________________________, soil conditions for plants,
medical diagnosis, soaps and shampoos, etc.
Sometimes we can use indicators, other times we might need a pH meter
4) How to measure pH with wide-range paper
5)
• ____________________the pH indicator paper strip with a few drops of solution
• Compare the color to the chart on the vial – then read the pH value.
Limitations to indicators:
• Usually given for a certain temperature (25oC), thus may change at different temperatures
•
Difficult to see _______________________________if the solution already has a color- like paint
•
The ability of the human ____________to distinguish colors is limited
6) pH Meter
•
A _________________________may give more definitive results
o some are large, others portable
o works by measuring the voltage between two electrodes;
typically accurate to within 0.01 pH unit of the true pH
o Instruments need to be calibrated
VII. Titration:
1) ___________________________= a procedure used in chemistry in order to determine the molarity of an acid or a
base.
• A chemical reaction is set up between a known volume of a solution of
__________________________________________________and a known volume of a solution with a known
concentration.
2) The relative acidity or basicity of an aqueous solution can be determined using the relative acid (base) equivalents.
• An ACID equivalent is equal to one mole of H+ or H3O+ ions.
• A BASE equivalent is equal to one mole of OH- ions.
o Note: some acids and bases are polyprotic, meaning each mole of the acid or base is capable of
releasing more than one acid or base equivalent.
4
3) When the solution of known concentration and the solution of unknown concentration are reacted to the point where
the number of acid equivalents equals the number of base equivalents (or vice
versa), the __________________________________________is reached.
•
4)
______________________________________= when the
moles of hydrogen ions is equal to the moles of hydroxide
ions (= neutralized!)
o The equivalence point of a strong acid & a strong base will
occur at________________.
o For weak acids and bases, the equivalence point need not
occur at pH
o There will be several equivalence points for polyprotic acids
and bases.
Use an Indicator
•
Often we use phenolphthalein- because it is colorless in
neutral and acid; turns pink in base
•
Relies on observing a ____________________________in the
solution.
•
The point at which the indicator changes color is called the________________________.
7) Titration steps:
1) A measured volume of acid of unknown concentration is added to a flask
2) Several drops of indicator added
3) A base of known concentration is slowly added using a buret, until the indicator changes color; measure the
volume
•
•
The solution of known concentration is called the _______________________
added by using a buret
Continue adding until the indicator changes color
called the “________________________” of the titration
VIII. Salts:
8) ____________________= a crystalline compound composed of the negative ion of an acid and the
positive ion of a base.
o _____________________________________= when acids and bases react with one another to
produce a salt and water
reaction of acid + base
Ex: HCl + NaHCO3
salt + water
NaCl + H2O + CO2
This is how you will neutralize an acid spill in upcoming labs!
Note: not all salts are neutral—can be acidic salts and basic salts
o ___________________________ = reaction of a salt with water to form an acidic or basic
solution
reverse of neutralization
5
IX. Acid-Base Behaviors:
•
___________________________= any oxide that will produce an acid when dissolved in water
Ex: ___________________- SO2 from fuel mixes with rain
SO2 (g)
+
H2O (l)
Acidic
anhydride +
•
H2SO3 (aq)
water
Acid
____________________________= any oxide that will produce a base when dissolved in water
Ex: ________________________________
Ex: Na2O (s) +
Basic
anhydride
+
H2O (l)
2NaOH (aq)
water
Base
IV. ACID RAIN:
1) _____________________________= a broad term referring to a mixture of wet and dry deposition (deposited
material) from the atmosphere containing higher than normal amounts of nitric and sulfuric acids.
•
Ex: SO2 from fuel mixes with rain
•
SO2 (g) + H2O (l)
H2SO3 (aq)
In the United States, roughly 2/3 of all SO2 and 1/4 of all NOx come from electric power
generation that relies on burning fossil fuels, like coal.
•
Occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to
form various acidic compounds.
•
The result is a mild solution of _____________________________and____________________.
A. Natural sources of nitrogen and sulfur oxides
•
•
•
Volcanoes erupting
Decaying vegetation
______________________________
•
Lightning bolts
B. Man-made sources of nitrogen and sulfur oxides
•
•
•
•
Power-generating plants (burning coal)
Ore smelting (uses heat and a chemical reducing agent to decompose the ore, driving off gasses
and leaving just the metal behind.)
Petroleum refining
Industrial furnaces
•
____________________________
6
C. Effects:
1) Causes acidification of _______________ and _______________
2) Contributes to the damage of _________________ at high elevations
3) Causes the ____________________of building materials and paints, including irreplaceable
buildings, statues, and sculptures that are part of our nation's cultural heritage
D. Ways to reduce acid rain:
1) Use coal containing ____________________________, washing the coal, and using devices called
“scrubbers” to chemically remove the SO2 from the gases leaving the smokestack
2) Use ________________________________________ sources: nuclear power, hydropower, wind
energy, geothermal energy, and solar energy_________________________________________ (a
naturally basic compound) can be added to acidic lakes to “cancel out” the acidity
7
Acids, Bases, Salts Worksheet
1) There are 3 common theories of acids and bases. Fill in the table below.
THEORY
ACID
BASE
Proton acceptor
Accept an electron pair
Release OH- in water
2) List 2 properties of an acid AND 2 properties of a base.
3) What is it that makes an acid considered to be “strong”?
4) What is it that makes a base considered to be “strong”?
5) What is it that makes a base considered to be “weak”?
6) What type of reaction is the following: acid + base
salt + water
_________________________________
7) What makes up an acid-base indicator?
8) Define acidic anhydride and give an example.
9) Define basic anhydride and give an example.
8
10) What causes acid rain?
11) What is one way to reduce acid rain? _______________________________________________
12) Draw the pH scale (include the values of acids, bases, neutral substances)
13) What is titration?
14) How do you know the end point/equivalence point is reached in a titration experiment?
15) What happens during a splint test, if oxygen gas is produced? _____________________________
16) What happens during a splint test, if hydrogen gas is produced? __________________________
17) What happens during a splint test, if carbon dioxide gas is produced? ______________________
18) Suppose you were testing vinegar with red and blue litmus paper. What would happen to
each type of litmus paper?
19) Suppose you were testing lye with red and blue litmus paper. What would happen to each
type of litmus paper?
20) What is the formula for the following acids?:
a. Hydrochloric acid = _______________
b. Nitric acid = ________________
c. Phosphoric acid = _____________
d. Acetic acid = __________________
e. Sulfuric acid = ________________
f. Carbonic acid = ________________
9
Unit Learning Map (6 days):
Acids & Bases
Mrs. Hostetter
Class: Academic Chemistry A - Grade 11: PA Standard 3.4.A Explain the concepts about the
structure and properties of matter.
Unit Essential Question(s):
Optional
Instructional Tools:
Why are acids and
bases so important in
everyday life?
Concept
Acids, Bases, Salts
Lesson Essential Questions:
What is the
difference between
an acid, base, or
salt?
Vocabulary:
Arrhenius
Bronsted-Lowry
Lewis
Litmus Test
Strong acids
Strong bases
pH scale
Concept
Guided Notes
Lab Materials: Titration lab,
indicators lab, Acids & metals
lab
Concept
Concept
Tests (experiments)
Lesson Essential Questions:
Lesson Essential Questions:
Lesson Essential Questions:
Vocabulary:
Vocabulary:
How can you
determine if a
substance is an acid or
base?
Vocabulary:
Acids/Base indicator
Titration
Salt
Neutralization
Hydrolysis
Acidic Anhydride
Basic anhydride
Acid rain
10
Acids & Bases Vocabulary:
1) Arrhenius (1887) =
-ACIDS produce H+ ions in aqueous solutions
-BASES produce OH- ions in aqueous solutions
2) Bronsted-Lowry (1923) =
-ACIDS are proton donors
-BASES are proton acceptors
3) Lewis (1923) =
-ACIDS are electron pair acceptors
-BASES are electron pair donors
4) Litmus test = paper made of a vegetable dye used to test for acidic or basic substances
• ACIDS = litmus paper changes from blue to red and red litmus paper stays red
• BASES = litmus paper changes from red to blue and blue litmus paper stays blue
5) Splint test = a test that can be performed in order to determine the type of gas that is produced in a chemical
reaction.
• Glowing splint goes out= CO2; Glowing splint get brighter= O2; Popping or “barking” sound is made = H2
6) Electrolyte = a solution that conducts electricity ( Ex: acids, bases, salts)
7) Strong Acids = Completely dissociate in water, forming H+ and an anion; 100% dissociation isn't true as
solutions become more concentrated. If the acid is 100% dissociated in solutions of 1.0 M or less, it is called
strong
8) Strong Bases = Dissociate 100% into the cation and OH- (hydroxide ion); The hydroxides of the Group I
and Group II metals usually are considered to be strong bases
9) pH scale = ranges from 0-14 to measure how acidic or basic a substance is; 0-6 are acids, 7 is neutral, 8-14
are bases
10) Acids/Base indicator = it is a weak acid or a weak base; it does not change color from pure acid to pure
alkaline at specific hydrogen ion concentrations; color change occurs over a range of hydrogen ion
concentrations
11) Titration = a procedure used in chemistry in order to determine the molarity of an acid or a base
12) Salt = a crystalline compound composed of the negative ion of an acid and the positive ion of a base
13) Neutralization reaction = when acids and bases react with one another to produce a salt and water
14) Hydrolysis = reaction of a salt with water to form an acidic or basic solution
15) Amphoteric = substance that can act as either an acid or a base
16) Acidic anhydride = any oxide that will produce an acid when dissolved in water; Ex: Acid Rain- SO2 from
fuel mixes with rain
17) Basic anhydride = any oxide that will produce a base when dissolved in water; Lime on farm fields
18) Acid rain = a broad term referring to a mixture of wet and dry deposition (deposited material) from the
atmosphere containing higher than normal amounts of nitric and sulfuric acids
11