Chapter 15 Study
expression that represents the concentration of H30+ ions in a solution
10^-14 / [OH-]
In acidic solutions, indicators are primarily in the form
HIn
in acidic solutions, most of the indicator is
HIn
During an acid-base titration, a rapid change in pH
occurs when the amounts of H30 ions and OH ions are neatly equal
What is monitored in an acid-base titration
pH
pH equation
pH = -log[H3O+]
pOH equation
pOH= -log[OH-]
indicators that change color at pH higher than 7 are used to determine
the equivalence point of a weak acid / strong base titration
the voltage changes as...
the hydronium ion concentration in the solution changes
pOH of a solution
the negative of the common logarithm of the hydroxide ion concentration, [OH-]
What is the pH of a household ammonia in which the H30 is 1.0 x 10 ^-12 M
12
The sum of the pH in the POH of a neutral solution at 25°C is
14
The neutralization of any strong acid and strong base produces mostly
H2O molecules
the pH of a solution is defined as
-log [H30+]
The pH scale in general use ranges from
0 to 14
What is the OH in a sample of lime juice with a pH of 2.0
1.0 x 10^-12 M
what is the concentration of hydronium ions in pure water
1.0 x 10^-7 M, Kw / [OH-], the same as [OH-]
Which of the following is the pH range for an indicator that is useful in studying neutralization is involving strong acids and weak bases
3.1 to 4.6
what is the pH of a 10^-4 M HCL solution
4
Using an indicator to determine pH is preferred over using a pH meter when
A quick and approximate answer is satisfactory
Universal indicators
Are mixtures of several indicator solutions
An acid-base titration determines the solution volumes that are
Chemically equivalent
in basic solutions, most of the indicator is
In-
the ionization constant of water
Kw
Liquid that is basic
Milk
Which of the substances is a weak base
NH3
When performing the calculation for a titration experiment, you need to have a balanced equation for the neutralization reaction in order to determine
The chemically equivalent amount of acid and base
A water solution is neutral if
The concentrations of H30 in 0H ions are equal
A pH meter measures the
Voltage difference between two electrodes in a solution
During an acid-base titration, a very rapid change in pH occurs
When roughly equivalent amount of H30 in 0H become present
Kw equation
[H3O+][OH-]= 1.0 x 10^-14
which is the following is not a property of an acidic solution
[HO-] greater than 1 x 10^-7 M
If the [H3O+] of a solution is known...
the [OH-] can be calculated using Kw and vice versa
for any acid titrated with a base, the equivalence point occurs when the
acid and bases are present in chemically equivalent amounts
below 7 on pH scale
acidic
An acid-base titration determines the volumes of two solutions that
are chemically equivalent
above 7 on pH scale
basic
the equivalence point of a weak acid/ strong base titration is
basic
Strong acids are considered...
completely ionized or dissociated in weak aqueous solutions
acid-base indicator
compounds whose colors are sensitive to pH
Titration
controlled addition and measurement of the amount of a solution of known concentration required to react completely with a measured amount of a solution of unknown concentration
A titration always involves the
controlled addition of a standard solution
if the pH of a solution increases from 2.0 to 4.0 the H30+ ions concentration
decreases by a factor of 100
pH meter
determines the pH of a solution by measuring the voltage between the two electrodes that are placed in the solution
A basic solution
has a lower concentration of hydronium ions than hydroxide ions
primary solution
highly purified solid compound used to check the concentration of the known solution in a titration
Neutralization occurs when
hydronium ions and hydroxide ions are supplies in equal numbers by reactants
A water solution whose pH is 7
is always neutral
The pH of a solution
is defined at the negative of a common logarithm of the hydronium ion concentration, [H3O+]
An acid-base indicator
is either a weak base or a weak acid, has a different color at a different pH, can be used to find the equivalence point
As the [H3O+] of a solution increases, the value of
log [H30+] increases, -log [H3O+], the solutions pH decreases
importance of a pH meter?
measures pH more precisely than indicators
7 on pH scale
neutral
An acid-base titration involves a
neutralization reaction
pure water partially breaks down into charged particles in a process called
self ionization
[H30+] > [OH-]
solution is acidic
[H3O+]=[OH-]
solution is neutral
[OH-]>[H3O+]
solutions are basic
An indicator, congo read, has a transition range of PH 3.0-5.0. It would be a good indicator for titrating
strong acid and a weak base
A solution that has a pH of 13 is a
strong base
Kw increases as...
temperature increases
The anti-log of a number N is
ten raised to the power of N
transition interval
the pH range over which an indicator changes color
equivilance point
the point at which the two solutions used in a titration are present in chemicals equivalent amounts
end point of an indicator
the point in a titration in which an indicator changes color
standard solution
the solution that contains the precisely known concentration of a solute
significant figures rule
there must be as many significant figured to the right of the decimal as there are in the number whose logarithm was found
indicators change colors because...
they are either weak acids or weak bases
self ionization of water
two water molecules produce a hydronium ion and a hydroxide ion by transfer of a proton
