Unit 8 - Acids and Bases Flashcards
What is the balanced chemical equation of autoionization of water?
2H2O H3O+ + OH-
What is the equilibrium constant of pure water at 25 degrees Celsius?
1 * 10^-14
Kw is equivalent to…
[H3O+][OH-]
The “p” in pH means…
to take the -LOG of the measurements that follow
In acidic solutions, ….
[H3O+] > [OH-]
In basic solutions, ….
[H3O+] < [OH-]
In neutral solutions, ….
[H3O+] = [OH-]
The pH scale measures …
the relative concentrations of H3O+ and OH-
As the concentration of H3O+ increases, the pH
decreases
What is the chemical formula for hydroxide ion?
OH-
What is the chemical formula for hydronium ion?
H3O+
In a pH of 7.345, the “7” represents …
the magnitude
In a pH of 7.345, the “345” represents ….
the measurement
From [H3O+] to pH …
[H3O+] = 10 ^ -pH
From pH to [H3O+] …
pH = -log [H3O+]
From [OH-] to pOH …
[OH-] = 10^-pOH
From pOH to [OH-] …
pOH = -log [OH-]
At 25 degrees Celsius, 14 is equivalent to…
pH + pOH
At 25 degrees Celsius, 1 * 10^-14 is equivalent to
[H3O+][OH-]
Pkw at 25 degrees Celsius is …
14
If [H3O+] has a coefficient of 1, then the pH is …
absolute value of the exponent.
If [H3O+] has a coefficient other than 1, then the pH is…
absolute value of the exponent minus one
The autoionization of water is an _________ process.
ENDOTHERMIC
As the temperature increases, the equilibrium constant will ….
Increase as well.
Kw increases with temperature because …
reaction shifts to form products and consume reactants
Products = [H3O+][OH-}
In pure water how does the concentration of OH- and H3O+ compare?
In PURE WATER [OH-} is EQUAL to {H3O+]
Kw is equal to….
10 ^ -pKW
pKw is equal to …
-log [Kw]
As temperature increase , the pH of pure water …
Decreases
How do we determine whether a solution is acidic, basic, or neutral at temperatures other than 25 degrees Celcius?
By comparing the concentrations of hydroxide to hydronium ion
Strong acids are assumed to ….
dissociate completely unless otherwise stated
Strong acids examples
HCl HBr HI HClO4 HClO3 HNO3 first H in H2SO4
Strong acid dissociation
HCl + H2O –> Cl- + H3O+
In pure water at 25 degrees Celsius, the concentration of OH- and H3O+ is equivalent to…
1.0 * 10 ^ -7 M
Strong bases are assumed to …
dissociate completely unless otherwise stated
Strong acids dissociate in water to produce …
H3O+ ions
Strong bases to dissociate in water to produce …
OH- ions
The net ionic equation for the mixing a strong acid and strong base is ….
OH- + H+ –> H2O
The neutralization reaction for mixing a strong acid and strong base is …
Strong acid + Strong Bases —> Water + Salt
Group 1 hydroxides include …
Oh
Group 2 hydroxides include …
Oh
When acids dissociate, only one …
“H’ is dissociate at a time.
[H3O+] is also known as …
H+
pH < pKa
acid has a higher concentration in the original solution
pH > pKa
conjugate acid has a higher concentration in the original solution
acid-base indicator
any substances that exhibit different properties in protonated/ deprotonated states
RESPOND to pH
Equivalence point
of moles of titrant added is EXACTLY sufficient to react completely with # of moles of titrated species
End point
point in titration at which indicator undergoes its color change
At the equivalence point pKa can be determined by…
taking the -log of Ka
At the equivalence point pKb can be determined by…
taking the -log of Kb
A titration graph of a weak acid titrated with a strong base looks like ….
forward “S”
A titration graph of a weak base titrated with a strong acid looks like…
backward “S”
Molecular structure of stronger acids
weak H-X bond where X is another element
Molecular structure of weaker acids
strong H-X bond where X is another element
Oxoacids/ Oxyacids
Contain an atom bonded to one or more oxygen atoms
inductive effect
Attraction of electrons in adjacent bonds by more electronegative atoms
Strong acids experience an inductive effect due to …
highly ELECTRONEGATIVE oxygen atoms
Polarity in strong acids draw electrons ….
AWAY from H- atom causing an EASIER IONIZATION
Weak acids do not experience a
STRONG induced dipole force
Polarity in weak acids are ….
less than in strong acids -> stronger bond between H+ and oxygen atom -> LESS IONIZABLE
If conjugate bases are less stable then…
a stronger base will result
Stronger acids results in …
Weaker bases
