acids always have as the state and always have a. naming acids and bases 6.1 theories of acids and...
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acids always have as the state and always have
A. Naming Acids and Bases 6.1 Theories of Acids and Bases
Chapter 6: Acids & Bases
Rules1. hydrogen becomes acid2. hydrogen becomes acid3. hydrogen becomes acid
____ide hydr____ic_____ate _____ic____ite ____ous
(aq)hydrogen
**Hydro and his side kick were skating, when they ate shit on ice, and became a little less rite chous.
Examples:
hydroiodic acid
phosphoric acid
nitrous acid
sulphurous acid
Change each of the following to the appropriate acid name and give the formula:
HI(aq)
H3PO4(aq)
HNO2(aq)
H2SO3(aq)
1. hydrogen iodide =
2. hydrogen phosphate =
3. hydrogen nitrite =
4. hydrogen sulphite =
most bases are ionic compounds that are named accordingly
Examples:
sodium hydroxide
sodium hydrogen carbonate magnesium hydroxide
ammonia
Name each of the following bases:
1. NaOH(aq) =
2. NaHCO3(aq) =
3. Mg(OH)2(aq) =
4. NH3(aq) =
IUPAC names for acids and bases are simply the word “aqueous” followed by the ionic name
Examples:
aqueous hydrogen iodide
aqueous magnesium hydroxide
aqueous hydrogen sulphite
aqueous sodium hydrogen carbonate
Write the IUPAC name for each of the following acids and bases:
1. hydroiodic acid =
2. magnesium hydroxide =
3. sulphurous acid =
4. sodium hydrogen carbonate =
B. Properties of Acids and Bases are
of a substance empirical properties observable properties
acids, bases and neutral substances have some properties that distinguish them and some that
are the same
Acids Bases Neutral Substances
sour bitter
electrolytes electrolytes electrolytes, non-electrolytes bases acids
indicators indicators do not
H2(g)
eg)HCl(aq), H2SO4(aq)
eg)NaCl(aq), Pb(NO3)2(aq)
eg) Ba(OH)2(aq) NH3(aq)
less than 7
greater than 7
of 7
litmus - litmus - bromothymol blue - bromothymol blue
-
red blue blue yellow
taste taste
neutralize neutralize
react with react with
react with to produce
metals
phenolphthalein - phenolphthalein - colourless
pink
affect indicators the same way
pH pH pH
first proposed theory on acids and bases
his theory was that some compounds form
his explanation of the properties of acids and bases is called the
electrically charged particles
Svante Arrhenius
Arrhenius theory of acids and bases
C. Arrhenius Definition
when in solution
an Arrhenius is a substance that to form in water
a will in an aqueous solution
base increase the [OH-(aq)]
base dissociateshydroxide ions, OH(aq),
an Arrhenius is a substance that (because it is molecular) to form
an will in an aqueous solution
acid increase the [H+(aq)]
acid ionizes hydrogen ions, H+(aq), in water
D. Modified Arrhenius Definition the original definition of acids and bases
proposed by Arrhenius is good but it has
some substances that might be predicted to be are actually
limitations
neutral basic
it has been found that not all bases contain the
eg) Na2CO3(aq), NH3(aq)
hydroxide ionas part of theirchemical formula
an Arrhenius is a substance that
in aqueous solution
base (modified)reacts with water
NH3(aq)eg)
OH(aq)+NH4+(aq)H2O()+
to produce OH(aq) ions
it has been found using analytical technology like X-ray crystallography that in an aqueous solution
when acids ionize, they produceH+(aq)eg) HCl(g) H+(aq) + Cl(aq)
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
H3O+
(aq)
this results in the formation of the hydronium ion
+Hydrogen ion
Water molecule
an Arrhenius is a substance that
in aqueous solution
acid (modified)reacts with water
HCl(aq) eg)
H3O+(aq) +Cl(aq)H2O()+
H2SO3(aq)
H3O+(aq) +HSO3
(aq) H2O()+
to produce H3O+(aq) ions
Review: Definitions of Acids and BasesReview: Definitions of Acids and BasesInitial Arrhenius Acid and Base Acids dissociate to form H+ ions
in a solution. Ex: HCl (aq) = H+
(aq) + Cl- (aq)
Bases dissociate to form OH- ions in a solution.
NaOH(aq) = OH- (aq) + Na+
(aq)
Wrong for bases that don’t finish with OH – doesn’t explain a few bases….
Modified Arrhenius Acid and Base Acids react with water to form
H3O+ ions in a solution. Ex:
Bases react with water to form OH- ions in a solution. (Only for bases that don’t finish with OH)
Practice a few!!!Practice a few!!!
Dissociate these acids and bases HNO3 (aq) + H2O (l)
HCOOH (aq) + H2O (l)
the of a substance depend on two things:
acidic and basic properties
1. the of the solution
2. the of the acid or base
6.2 Strong and Weak Acids and Bases
concentration
identity
A. Strong Acids and Weak Acids
an acid that ionizes almost in water is called a
100% of the becomes
strong acid100%
eg) HCl(aq) + H2O() Cl(aq)+H3O+(aq)
HCl(aq) 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 andreact vigorously with metals
there are 6 strong acids:
HNO3(aq)
H2SO4(aq)
HCl(aq)
HI(aq)
HBr(aq)
HClO4(aq)
nitric acid
sulfuric acid
hydrochloric acid
hydroiodic acid
hydrobromic acid
perchloric acid
***on your periodic table
a and only a small percentage of the acid formsweak acid does not ionize 100%
react much less vigorously with metals
ions in solution
we use the for weak acids
eg)
CH3COOH(aq) + H2O()⇌ CH3COO(aq)+H3O+(aq)
equilibrium arrow
weak acids are weak electrolytes and
B. Strong Bases and Weak Bases
a base that dissociates into ions in water is called a
are strong bases
strong base100%
a and only a small percentage of the base forms
we use the for weak bases
ionic hydroxides and metallic oxides
eg) NaOH(aq) OH(aq)+Na+(aq)
ions in solution
weak base does not dissociate 100%
eg) NH3(aq) + H2O() ⇌ OH(aq)+NH4+(aq)
equilibrium arrow
C. Monoprotic and Polyprotic Acids
acids that have only per molecule that can are called
monoprotic acids can be
eg) CH3COOH(aq)HNO3(aq),HF(aq),HCl(aq),
strong or weak
one hydrogen atomionize
monoprotic acids
acids that contain that can are called
eg) H3PO4(aq)H2SO4(aq),
acids with are , with are
two hydrogens diproticthree hydrogens triprotic
two or more hydrogen atomsionize polyprotic acids
when polyprotic acids ionize, only hydrogen is removed at a time, with each acid becoming
one
progressively weaker
eg)
HSO4(aq)
HSO4(aq)+H3O
+(aq)
SO42(aq)+H3O
+(aq)H2O()+
H2O()+H2SO4(aq)
D. Monoprotic and Polyprotic Bases
bases that are called
bases that react with water in are called
eg) NaOH(s)
react with water in only one step to form hydroxide ions monoprotic bases
two or more stepspolyprotic bases
eg) CO32(aq), PO4
3(aq)
***complex ions with more than 1- charge!!!
as with polyprotic acids, only
eg)
HCO3(aq)
HCO3(aq)+OH(aq)
H2CO3(aq) +OH(aq) H2O()+
H2O()+CO32(aq)
one OH(aq) is formed at a time, and each new base formed is than the last
weaker
E. Neutralization
the reaction between an acid and a base produces an
the products of are both
ionic compound and water
neutralneutralization
in a neutralization reaction or between a , the product is alwayswater
strong acid and a strong baseacid-base reaction
H3O+
(aq)2 H2O()OH(aq)+
water acid + base → a salt +
eg) HCl(aq) + KOH(aq) →KCl(aq) + HOH()
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
the two ways to deal with acid or base spills are: 1. dilution:
2. neutralization:
reduce the by adding
you always use a for the neutralization so you aren’t left with another hazardous situation
concentrationwater
weak acid or base
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 ionshydroxide 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
the concentration of and are
6.3 Acids, Bases and pH
B. The pH Scale
in 1909, Soren Sorenson devised the
it is used because the [H3O
+(aq)] is
pH scale
very small
at 25C (standard conditions), most solutions have a pH that falls between0.0 and
it is possible to have a pH and a pH
it is a based on whole numbers that are powers of 10
logarithmic scale
14.0
negativeabove 14
there is a for every change in on the pH scale
10-fold change in [H3O+
(aq)]
a solution with a pH of 11 is times more basic than a solution with a pH of 9
10 10 = 100
pH Scale
0 7 14
more acidic more basic
neutral
1
eg)
Try These:
1. [H3O+(aq)] = 1 x 10-10 mol/L pH =
2. [H3O+(aq)] = 1.0 x 10-2 mol/LpH =
3. [H3O+(aq)] = 6.88 x 10-3 mol/L pH =
4. [H3O+(aq)] = 9.6 x 10-6 mol/LpH =
pH = log [H3O+
(aq)]
10
2
2.1
5.0
C. Calculating pH and pOH
***New sig dig rule: when reporting pH or pOH values, only the numbers to the count as significant
right of the decimal place
Example6.30 g of HNO3 is dissolved in 750 mL of water. What is the pH ?
HNO3(aq) m = 6.30 gM = 63.02 g/molV = 0.750 L
c = 0.133…mol/L x 1/1 = 0.133…mol/L
pH = -log[H+(aq)] = -log[0.133… mol/L] = 0.875
+ NO3-(aq)H+(aq)
n = m M = 6.30 g 63.02 g/mol = 0.0999…mol
c = n V = 0.0999…mol 0.750 L = 0.133…mol/L
just as deals with deals with
***p just means log
pH [H3O+(aq)], pOH
[OH(aq)]
at SATP…pH + pOH = 14
pOH
pH
0
7 014
7 14
3
11
9
5 9
5
3
11 113
131
to calculate the use the same formulas as pH but substitute the
pOH,[OH(aq)]
pOH = log[OH(aq)]
Try These:
1. [OH(aq)] = 1.0 10-11 mol/L pOH =
2. [OH(aq)] = 6.22 10-2 mol/LpOH =
3. [OH(aq)] = 9.411 10-6 mol/LpOH =
4. [OH(aq)] = 2 10-6 mol/LpOH =
11.00
1.206
5.0264
5.7
Summarizing pH and POHSummarizing pH and POH
pH – concentration of H+ in your solution .0 = strong acid, 7 = neutral, 14 = strong base
pOH – concentration of OH- in your solution. 14 = strong acid, 7 neutral, 0 = strong base
pH = log [H3O+
(aq)] pOH = log[OH(aq)]
pH + pOH = 14
Bases = [OH(aq)]Acids = [H3O+(aq)],
[H3O+(aq)] = 10-pH
you could also be given the pH or pOH and asked to calculate the [H3O
+(aq)] or [OH-(aq)]
[OH(aq)]= 10-pOH
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)] =
0.1 mol/L
6 10-14 mol/L
1.3 10-7 mol/L
0.164 mol/L
1 x 10-4 mol/L
6.2 x 10-7
mol/L
10-7 mol/L
3.98 x 10-14
mol/L
Summary of pH/pOH and concentration
-log [H3O+] = to find pH
-log [OH-] = to find OH
10-pH = to find concentration of [H3O+] 10-pOH = to find concentration of [OH-]
9. Complete the following table:
[H3O+(aq)] [OH(aq)] pH pOH Acid/Base/
Neutral
4.0 x 10-6 mol/L
10 mol/L
2.0 1011 mol/L
15.00
9.500
1.36
5.40 8.602.5 x 10-9 mol/L
4.500
15.00
-1.00
12.64
-1.00
3.30 10.705.0 x 10-4 mol/L
1.0 x 10-15 mol/L
10 mol/L1.0 x 10-15 mol/L
3.16 x 10-5 mol/L3.16 x 10-10 mol/L
2.3 x 10-13 mol/L 0.044 mol/L
acid
base
acid
acid
base
base
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 indicatorchanges colour
they can bedried onto strips of paper
eg) litmus paper, pH paper
they can besolutions
eg) bromothymol blue, universal indicator, indigo carmine etc
they can be made from natural substances eg) tea, red cabbage juice, grape juice
each indicator has a where it will
specific pH rangechange colour
you can use to approximate the
two or more indicatorspH of a solution
pH Meters using a pH meter is the most
way of measuring
it has an that compares the [H3O
+(aq)] in the solution to a and it will give a of the pH
precise
electrodestandard
digital readout
pH
E. Diluting an Acid or Base
when you to an , you change the
diluting an acid will the until a pH of is reached
[H3O+(aq)] or the [OH(aq)]
add water acid or base
decrease [H3O+(aq)]
7.0
diluting a base will the until a pH of is reached
decrease [OH-(aq)]7.0
Remember: CiVi = CfVfRemember: 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?
Formulas to remember:
pH = - log [H3O+]
pOH = - log [OH-]
[H3O+] = 10-pH
[OH-] = 10-pOH
C = n/v
CiVi = CfVf
Review Assignment:Textbook p. 244 #1-28