acids always have as the state and always have

1
Chapter 6 Acids Bases
6.1 Theories of Acids and Bases
A. Naming Acids and Bases

• acids always have as the state and
  always have

(aq)
hydrogen
Rules 1. hydrogen
becomes acid 2.
hydrogen becomes
acid 3. hydrogen
becomes
acid
____ide
hydr____ic
_____ate
_____ic
____ite
____ous
2
Examples
Change each of the following to the appropriate
acid name and give the formula
HI(aq)
hydroiodic acid
1. hydrogen iodide
H3PO4(aq)
phosphoric acid
2. hydrogen phosphate
nitrous acid
HNO2(aq)
3. hydrogen nitrite
sulphurous acid
H2SO3(aq)
4. hydrogen sulphite
3

• most bases are ionic compounds that are named
  accordingly

Examples
Name each of the following bases
sodium hydroxide
1. NaOH(aq)
sodium hydrogen carbonate
2. NaHCO3(aq)
magnesium hydroxide
3. Mg(OH)2(aq)
ammonia
4. NH3(aq)
4

• IUPAC names for acids and bases are simply the
  word aqueous followed by the ionic name

Examples
Write the IUPAC name for each of the following
acids and bases
aqueous hydrogen iodide
1. hydroiodic acid
2. magnesium hydroxide
aqueous magnesium hydroxide
aqueous hydrogen sulphite
3. sulphurous acid
4. sodium hydrogen carbonate
aqueous sodium hydrogen carbonate
5
B. Properties of Acids and Bases
empirical properties
observable properties

• are
  of a
  substance

• acids, bases and neutral substances have some
  properties that distinguish them and some that

are the same
6
Neutral Substances
Acids
Bases

sour
taste
bitter
taste

electrolytes
electrolytes

electrolytes, non-electrolytes

acids
neutralize
bases
neutralize

indicators
do not
react with

indicators
react with
affect indicators the same way
litmus -
litmus -
red
blue
bromothymol blue -
bromothymol blue -
blue
yellow
phenolphthalein -
phenolphthalein -
pink
colourless

react with to produce
metals
H2(g)

pH
greater than 7
pH
of 7

pH
less than 7
eg)
HCl(aq), H2SO4(aq)
eg)
eg)
Ba(OH)2(aq) NH3(aq)
NaCl(aq), Pb(NO3)2(aq)
7
C. Arrhenius Definition

• first
  proposed theory on acids and bases

Svante Arrhenius

• his theory was that some compounds form

electrically charged particles
when in
solution

• his explanation of the properties of acids and
  bases is called the

Arrhenius theory of acids and bases
8

• an Arrhenius is a substance that
  (because it is molecular) to form

acid
ionizes

hydrogen ions, H(aq), in water

• an will
  in an aqueous solution

acid
increase the H(aq)

• an Arrhenius is a substance that
  to form
  in water

base
dissociates
hydroxide ions, OH?(aq),

• a will
  in an aqueous solution

base
increase the OH-(aq)
9
D. Modified Arrhenius Definition

• the original definition of acids and bases
  proposed by Arrhenius is good but it has

limitations

• some substances that might be predicted to be
  are actually

neutral
basic
eg)
Na2CO3(aq), NH3(aq)

• it has been found that not all bases contain the

hydroxide ion
as part of their
chemical formula
10

• an Arrhenius
  is a substance that
  in aqueous
  solution

base (modified)
reacts with water
to produce
OH?(aq) ions
eg)
?
NH3(aq)
OH?(aq)

NH4(aq)
H2O(?)

11

• when acids ionize, they produce

H(aq)
eg) HCl(g) ? H(aq) Cl?(aq)

• it has been found using analytical technology
  like X-ray crystallography that
  
  in an aqueous solution

H(aq) ions do not exist in isolation

• the hydrogen ion is extremely positive in charge
  and water molecules themselves are very polar so
  it is that
  would exist in water
  without being attracted to the
  of other

highly unlikely
hydrogen ions
negative poles
water molecules
12

• this results in the formation of the

hydronium ion

H3O(aq)
13

• an Arrhenius
  is a substance that
  in aqueous solution

acid (modified)
reacts with water
to produce
H3O(aq) ions
eg)
?
HCl(aq)
H3O(aq)

Cl?(aq)
H2O(?)

?
H2SO3(aq)
H3O(aq)

HSO3?(aq)
H2O(?)

H2O(?)
SO2 (?)
14
6.2 Strong and Weak Acids and Bases

• the
  of a substance depend on two
  things

acidic and basic properties
1.
the of the
solution
concentration
2.
the of the acid or base
identity
15
A. Strong Acids and Weak Acids
100

• an acid that ionizes almost in
  water is called a

strong acid
eg) HCl(aq) H2O(?) ?
Cl?(aq)

H3O(aq)
HCl(aq)

• 100 of the becomes

H3O(aq) and Cl?(aq)

• the concentration of the is
  the as the concentration of the
  it came from

H3O(aq)
same
acid

• strong acids are

strong electrolytes
and
react vigorously with metals
16

• there are 6 strong acids

HClO4(aq)
perchloric acid
hydrobromic acid
HBr(aq)
HI(aq)
hydroiodic acid
HCl(aq)
hydrochloric acid
H2SO4(aq)
sulfuric acid
HNO3(aq)
nitric acid
on your periodic table
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weak acid does not ionize 100

• a
  and only a small
  percentage of the acid forms

ions in solution
eg) CH3COOH(aq) H2O(?)
?

H3O(aq)
CH3COO?(aq)

• we use the
  for weak acids

equilibrium arrow

react much less
vigorously with metals

• weak acids are

weak electrolytes and
18
B. Strong Bases and Weak Bases
100

• a base that dissociates into ions
  in water is called a

strong base
ionic hydroxides and metallic oxides

• 
  are strong bases

eg) NaOH(aq) ?
OH?(aq)

Na(aq)

• a
  and
  only a small percentage of the base forms

weak base does not dissociate 100
ions in solution

NH4(aq)
eg) NH3(aq) H2O(?) ?
OH?(aq)

• we use the
  for weak bases

equilibrium arrow
19
C. Monoprotic and Polyprotic Acids
one hydrogen atom

• acids that have only
  per molecule that can
  are called

ionize
monoprotic acids
eg)
CH3COOH(aq)
HNO3(aq),
HF(aq),
HCl(aq),

• monoprotic acids can be

strong or weak
20

• acids that contain
  that can
  are called

two or more hydrogen atoms
ionize
polyprotic acids
eg)
H3PO4(aq)
H2SO4(aq),

• acids with are
  , with
  are

two hydrogens
diprotic
three hydrogens
triprotic
21

• when polyprotic acids ionize, only
  hydrogen is removed at a time, with each acid
  becoming

one
progressively weaker
eg)
?
HSO4?(aq)

H2O(?)

H3O(aq)
H2SO4(aq)

HSO4?(aq)
SO42?(aq)

H3O(aq)
?
H2O(?)
22
D. Monoprotic and Polyprotic Bases
react with water in only one
step to form hydroxide ions

• bases that
  
  are called

monoprotic bases
eg) NaOH(s)

• bases that react with water in
  are called

two or more steps
polyprotic bases
eg) CO32?(aq), PO43?(aq)
complex ions with more than 1- charge!!!
23
one

• as with polyprotic acids, only

OH?(aq) is formed at a time, and
each new base formed is than
the last
weaker
eg)
?
HCO3?(aq)

H2O(?)

OH?(aq)
CO32?(aq)

HCO3?(aq)
H2CO3(aq)

OH?(aq)
?
H2O(?)
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E. Neutralization

• the reaction between an acid and a base produces
  an

ionic compound and water
water
acid

base
a salt

?
KCl(aq) HOH(?)
eg) HCl(aq) KOH(aq) ?

• the products of
  are both

neutral
neutralization

• in a neutralization reaction or
  between a
  , the
  product is always

acid-base reaction
strong acid and a strong base
water
H3O(aq)
2 H2O(?)
?
OH?(aq)

25
F. Acid and Base Spills

• there are many uses for both acids and bases in
  our households and in industry

• due to their,
  special care must be
  used when they are being

reactivity and corrosiveness

produced and transported
26

• the two ways to deal with acid or base spills
  are

concentration
1. dilution
reduce the
by adding
water

weak acid or base
2. neutralization
you always use
a for the
neutralization so you arent left with another
hazardous situation
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6.3 Acids, Bases and pH
A. Ion Concentration in Water

• the self-ionization of water is very

small
(only 2 in 1 billion)
?
H3O(aq)
OH-(aq)


H2O(?)
H2O(?)
hydronium ions

• the concentration of
  and
  are

hydroxide ions
equal
and constant in pure water
H3O(aq) OH-(aq)
1.0 x 10-7 mol/L
1.0 x 10-7 mol/L
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B. The pH Scale

• in 1909, Soren Sorenson devised the

pH scale

• it is used because the H3O(aq) is

very small

• at 25?C (standard conditions), most solutions
  have a pH that falls between

0.0 and
14.0

• it is possible to have a pH
  and a pH

negative
above 14

• it is a
  based on whole numbers that are powers of 10

logarithmic scale
29

• there is a
  for every change in
  on the pH scale

10-fold change in H3O(aq)
1
a solution with a pH of 11 is
times more basic than a solution with
a pH of 9
10 ? 10 100
eg)
pH Scale
more acidic
more basic
neutral
30
C. Calculating pH and pOH
pH ? log H3O(aq)
when
reporting pH or pOH values, only the numbers to
the
count as significant
New sig dig rule

right of the decimal place
Try These 1.     H3O(aq) 1 x 10-10 mol/L pH
2.     H3O(aq) 1.0 x 10-2 mol/L pH
3.     H3O(aq) 6.88 x 10-3 mol/L pH
4.     H3O(aq) 9.6 x 10-6 mol/L pH
10.0
2.00
2.162
5.02
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Example 6.30 g of HNO3 is dissolved in 750 mL of
water. What is the pH ?

NO3-(aq)
H(aq)
?
HNO3(aq)
m 6.30 g M 63.02 g/mol V 0.750 L
c 0.133mol/L x 1/1 0.133mol/L
n m M 6.30 g 63.02 g/mol
0.0999mol
pH -logH(aq) -log0.133 mol/L
0.875
c n V 0.0999mol 0.750 L
0.133mol/L
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H3O(aq),

• just as deals with
  deals with

pH
pOH
OH?(aq)
p just means ?log

• at SATP

pH pOH 14
pH
0
7
14
11
5
9
3
13
1
7
0
14
3
9
5
11
1
13
pOH
33

• to calculate the use the same
  formulas as pH but substitute the

pOH,
OH?(aq)
pOH ? logOH?(aq)
Try These 1.     OH?(aq) 1.0 ? 10-11
mol/L pOH 2.     OH?(aq) 6.22 ? 10-2
mol/L pOH 3.     OH?(aq) 9.411 ? 10-6
mol/L pOH 4.     OH?(aq) 2 ? 10-6
mol/L pOH
11.00
1.206
5.0264
5.7
34

• you could also be given the pH or pOH and asked
  to calculate the

H3O(aq) or OH-(aq)
H3O(aq) 10-pH
OH?(aq) 10-pOH
35
Try These 1.     pH 4.0 H3O(aq) 2.    
pH 6.21 H3O(aq) 3.     pH
13.400 H3O(aq) 4.     pH 7 H3O(aq)
5.     pOH 1.0 OH?(aq) 6.     pOH
13.2 OH?(aq) 7.     pOH 6.90 OH?(aq)
8.     pOH 0.786 OH?(aq)
1 x 10-4 mol/L
6.2 x 10-7 mol/L
3.98 x 10-14 mol/L
10-7 mol/L
0.1 mol/L
6 ? 10-14 mol/L
1.3 ? 10-7 mol/L
0.164 mol/L
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9. Complete the following table
5.40
8.60
acid
4.0 x 10-6 mol/L
2.5 x 10-9 mol/L
9.500
4.500
base
3.16 x 10-5 mol/L
3.16 x 10-10 mol/L
3.30
10.70
acid
2.0 ? 10?11 mol/L
5.0 x 10-4 mol/L
15.00
10 mol/L
-1.00
acid
1.0 x 10-15 mol/L
base
-1.00
10 mol/L
15.00
1.0 x 10-15 mol/L
base
1.36
12.64
0.044 mol/L
2.3 x 10-13 mol/L
37
D. Measuring pH

• pH can be measured using

1. acid-base indicators
2. pH meter
Indicators

• an
  is any chemical that
  in an acidic or basic solution

acid-base indicator
changes colour

• they can be

dried onto strips of paper
eg) litmus paper, pH paper
38

• they can be

solutions
eg) bromothymol blue, universal indicator, indigo
carmine etc

• they can be made from

natural substances
eg) tea, red cabbage juice, grape juice
39

• each indicator has a
  where it will

specific pH range
change colour

• you can use
  to approximate the

two or more indicators
pH of a solution
40
pH Meters

• using a pH meter is the most
  way of measuring

precise
pH

• it has an that compares
  the H3O(aq) in the solution to a
  and it will give a
  of the pH

electrode
standard
digital readout
41
E. Diluting an Acid or Base
add water
acid or base

• when you to an
  , you change the

H3O(aq) or the OH?(aq)

• diluting an acid will the
  until a pH of is
  reached

H3O(aq)
decrease
7.0

• diluting a base will the
  until a pH of is
  reached

OH-(aq)
decrease
7.0
42
Remember CiVi CfVf

• A concentrated solution is made by dissolving 5g
  of HCl into 30 L of water. You then take 10 mL
  of this solution and dilute it to a volume of 50
  L. What is the pH of the diluted solution?

43
Formulas to remember
pH - log H3O
pOH - log OH-
H3O 10-pH
OH- 10-pOH
C n/v
CiVi CfVf
44

• Review Assignment
• Textbook p. 244 1-28