LEQ: What techniques in the lab setting will be used
to identify acids and bases?
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
Acids
Bases
 Produce H+ ions in
water
 Produce OH(hydroxide) ions in
 Form hydronium ions
(H30+)
water
 Feel slippery
 Taste bitter, chalky
 Change litmus paper
blue
 Taste sour
 Produce hydrogen gas
when react with metals
 Change litmus paper
red
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 How are they alike?
 Corrosive
 React with indicators and change color
 Conduct electricity (electrolytes)
 React with each other to form salt and water
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 Common Acids
Soda
Coffee
Wine
Grapefruit (citric acid)
Yogurt (lactic acid)
Pickled foods in vinegar (acetic acid or CH₃COOH)
Fertilizers (sulfuric, nitric, phosphoric, HCL)
Car batteries (sulfuric acid or H₂SO₄)
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 Common bases
Egg whites
Baking powder
Milk of magnesia
Mg(OH)2
Antacids – Al(OH)3
Soap - NaOH
Shampoo
Ammonia - NH3
Oven cleaner - NaOH
Drain cleaner - NaOH
Fertilizers – NH3
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 What does it mean to dissociate?
 To break apart
 Process in which an ionic compound
separates into its positive and negative
ions
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 How do acids dissociate in water and what
products are formed?
 The negative areas of nearby6 water
molecules attract the positive hydrogen in
the acid.
 Produces a hydronium ion and an anion
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 How do bases dissociate in water and what
products are formed?
 The negative areas of nearby water molecule
attract the positive ion in the base. The positive
area of the water molecule attract the hydroxide
ion.
 Water molecules do not combine with the ions
formed from the base.
 Produces a positive ion, a hydroxide ion, and water
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 Explain how ammonia (NH3) is considered a
base when it does not contain OH-.
 The ammonia attracts a hydrogen from the
water forming ammonium ion and a
hydroxide ion.
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
Identify each as characteristic of an A) acid or B)
base
____ 1. Sour taste
____ 2. Produces OH- in aqueous solutions
____ 3. Chalky taste
____ 4. Is an electrolyte
____ 5. Produces H+ in aqueous solutions
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
Describe the solution in each of the following as: 1)
acid 2) base or 3)neutral.
A. ___soda
B. ___soap
C. ___coffee
D. ___ wine
E. ___ water
F. ___ grapefruit
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
Identify each as a characteristic of an A) acid or B)
base
_A_ 1. Sour taste
_B_ 2. Produces OH- in aqueous solutions
_B_ 3. Chalky taste
A, B 4. Is an electrolyte
_A_ 5. Produces H+ in aqueous solutions
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
Describe each solution as:
1) acid 2) base or 3) neutral.
A. _1_ soda
B. _2_ soap
C. _1_ coffee
D. _1_ wine
E. _3_ water
F. _1_ grapefruit
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
Strong acids
 Nearly all acids




molecules dissociate into
ions
Strong electric current
Single arrow in chemical
equation
HCl + H2O  H3O+ + ClExample: HCl, HNO3,
H2SO4
Weak acids
 Partially dissociate into
ions in water
 Weak electric current
 Double arrow in chemical
equation
 CH3COOH + H2O
H3O+ + CH3COO Examples: acetic acid,
carbonic acid
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 Differentiate between strong and weak bases.
 Strong completely dissociates and weak partially
dissociates.
 NaOH  Na + + OH NH3 + H2O
NH4+ + OH-
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 Differentiate between strength and concentration.
 Strength
 Strong or weak
 How easily acids and bases dissociate in water
 Concentration
 Concentrated – a large amount of acid or base in a given
amount of water
 Diluted – a little acid or base in a large amount of water
 Amount of acid or base dissolve
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 pH scale - measures how acidic or basic a solution is





based on concentration of H+ions
Ways to test pH
pH paper
pH meter
****litmus paper just tells if it is an acid or base****
Buffers – used to minimize the effects of acids or bases
on pH
 pH lower than 7: acidic (high H+ concentration)
 pH higher than 7: basic (low H+ concentration)
 pH at 7: neutral
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 Neutralization
 A chemical reaction between an acid and a base that
takes place in a water solution
H+ + OH-  H2O
Cl- + Na+  NaCl
 Therefore,
acid + base  salt + water
HCl + NaOH  H2O + NaCl
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 What is titration?
 When a solution of known concentration and volume
is used to determine the concentration of another
solution
LEQ: What techniques in the lab setting will be
used to identify acids and bases?
 What are the steps of titration?
 Place a known volume of acid that has an unknown
concentration in a beaker
 Add a few drops of phenolphthalein (indicator) to
beaker (colorless in acid but turns bright pink in base)
 Slowly add base solution of known concentration
(standard solution) to acid and indicator solution
using the burette system
 Continue to add base drop by drop until solution turns
pink and the color persist (end
solution/neutralization)
LEQ: What are some causes and effects of acid
rain?
 Causes:
 Burning of fossil fuels
 Effects:
 Corrode or eat away at substances
 Destroy plant and animal life
 Solutions:
 Reduce pollution
 Add lime to acidic water
Differentiate between acids and
bases
 Acids produce hydrogen ions which attach
to the water molecule forming a hydronium
ion. They turn litmus paper red, are low on
the pH scale and taste sour.
 Bases produce hydroxide ions in solution.
They turn litmus paper blue, have a high
pH, and taste bitter or chalky.
How are acids and bases alike?
 Both acids and bases are corrosive to metals
and can burn tissue. They change colors in
the presence of indicators. They both
produce electrolytes meaning that they have
the ability to conduct electricity. When they
react with each other to form salt and water.
What is an example of an
indicator?
 Litmus paper
 phenolphthalein
Explain the process of dissociation
of bases and be specific on what
products are produced.
 When a base is added to water, the water
molecule dissociates the base forming a
cation and a hydroxide ion. The water
molecule remains as a water molecule.
Explain the process of dissociation
of acids and be specific on what
products are produced.
 When an acid is added to water, the negative
side of the water molecule removes the
hydrogen from the acid forming a
hydronium ion and leaving an anion.
Explain in detail how ammonia
dissociates in water. Explain how
this proves that ammonia is a base.
 Ammonia does not have a hydroxide ion as
part of its formula. When ammonia is added
to water, it removes a hydrogen ion from the
water molecule leaving behind a hydroxide
ion. The removed hydrogen attaches to the
ammonia creating the ammonium ion. Due
to the hydroxide ion being produced, this
proves that ammonia is a base.
Differentiate between strong
acids/bases and weak acids/bases.
 Strong acids and bases dissociate completely in water.
Strong acids have low pH numbers and strong bases
have high pH numbers. Both of their equations
contain a single arrow pointing toward the product
side. Strong acids and bases both have the ability to
produce a strong electric current.
 Weak acids and bases partially dissociate in water.
Their pH numbers are closer toward the middle of the
pH scale with the exception to 7 (seven) which is
neutral. Their equations contain a double arrow. Weak
acids and bases only produce a small electric current.
Differentiate between strength and
concentration.
 Strength refers to the ease at which acids and bases
dissociate in water. If they dissociate completely; then,
they are strong. If they only partially dissociate; then,
they are weak.
 Concentration refers to the amount of acid or base
present in a solution. The solution is considered
concentrated if there is large amount of acid or base
and little water. The solution is considered diluted if
there is minimal amounts of acid or base in a large
amount of water.
What is the purpose of buffers?
 Buffers are used to minimize the effects of acids or
bases on pH within the body so that the pH level of the
body stays close to neutral.