Chapter 15 Flashcards
Define carboxylic acid
the Organic acid containing the functional group -COOH
What is the Arrhenius definition of an acid?
A substance that produces H+ ions in aqueous solution
What is the Arrhenius definition of a base?
A substance that produces OH- ions in aqueous solution
Define Arrhenius definition
The definitions of an acid as a substance that produces H+ ions in aqueous solution and a base as a substance that produces OH- ions in an aqueous solution
Define hydronium ion
H₃0⁺, the ion formed from the association of a water molecule with an H+ ion donated by an acid
Can H+ and H₃0⁺ be used interchangeably?
Yes
Do H+ ions associate with water molecules to form hydronium ions?
Yes! Always!
When covalently bonded acids are dissolved in water they _____. When ionically bonded bases are dissolved in water they _____.
ionize
dissociate
Under the Arrhenius definition the combination of acid and base results in ____ because…?
water because H+ and OH- naturally combine to form neutral water
Define Brønsted-Lowry definition
The definitions of an acid as a proton (H+ ion) donor and a base as a proton acceptor.
What is the Brønsted-Lowry definition of an acid?
A proton donor (where a proton is an H+ ion)
What is the Brønsted-Lowry definition of a base?
A proton acceptor (where a proton is an H+ ion)
Define amphoteric
Able to act as either a base or an acid (like water)
Define conjugate acid-base pair
Two substance related to each other by the transfer of a proton
Define conjugate acid
Any base to which a proton has been added
Define conjugate base
Any acid from which a proton has been removed
A(n) ____ accepts a proton and becomes a conjugate ____.
base
acid
A(n) ____ donates a proton and becomes a conjugate ____.
acid
base
Define strong acid
An acid that complete;y ionizes in solution
A ____ acid completely ionizes in solution.
strong
A _____ acid only partially ionizes in solution.
weak
The degree to which an acid is strong or weak depends on …?
The attraction between the anion of the acid (the conjugate base) and the hydrogen ion, relative to the attractions of these ions to water
In general, the stronger the acid, the ____ the conjugate base and vice versa
weaker
If the the forward reaction (that of the acid) has a high tendency to occur, then the reverse reaction (that of the conjugate base) has a ____ tendency to occur
low
Define acid ionization constant (Ka)
The equilibrium constant for the ionization of a weak acid; used to compare the relative strengths of weak acids
How can we quantify the relative strengths of weak acids?
Using the acid ionization constant (Ka)
The ____ _____ ___ is the equilibrium constant for the ionization reaction of a weak acid
acid ionization constant
A ____ base is a base that completely dissociates in solution
strong
Most strong bases are ____ ____ from group 1 or 2
metal hydroxides
What groups are most strong bases formed from (in the form of metal hydroxides)?
Group 1 or 2
Define weak base
A base that only partially ionizes in water
The most common weak bases produce OH- by …?
accepting a proton from water, ionizing water to form OH-
Define base ionization constant (Kb)
The equilibrium constant for the ionization reaction of a weak base; used to compare the relative strength of weak bases
The smaller the value of Kb, the _____ the base
weaker
Define autoionization
The process by which water acts as an acid and a base with itself.
Define ion product constant for water (Kw)
The equilibrium constant for the auto ionization of water
What is the ion product constant for water alternatively called?
dissociation constant for water
What is the value of Kw at 25ºC?
1.0 x 10⁻¹⁴
define neutral
The state of a solution where the concentrations of H₃0⁺ and OH- are equal
Define acidic solution
a solution containing an acid that creates additional H₃0⁺ ions, causing [H₃0⁺] to increase
If the concentration of H₃0⁺ is greater than the concentration of OH- is [H₃0⁺][OH⁻] = Kw = 1.0 x 10⁻¹⁴ still true?
Yes! This is always true!
If the concentration of H₃0⁺ is less than the concentration of OH- is [H₃0⁺][OH⁻] = Kw = 1.0 x 10⁻¹⁴ still true?
Yes! This is always true!
In an acidic solution [H₃0⁺] is ___ than [OH⁻].
greater
In a basic solution [H₃0⁺] is ___ than [OH⁻].
less
Define basic solution
A solution containing a base that creates additional OH- ions, causing the [OH-] to increase
A(n) ____ solution contains [H₃0⁺] = [OH⁻] = 1.0 x 10⁻⁷ mol/L (at 25ºC)
neutral
A(n) ____ solution contains [H₃0⁺] > [OH⁻]
acidic
A(n) ____ solution contains [H₃0⁺] < [OH⁻]
basic
In all ____ solutions both H₃0⁺ and OH⁻ are present, with [H₃0⁺][OH⁻] = Kw = 1.0 x 10⁻¹⁴ (at 25ºC)
aqueous
Define pH
The negative log of the concentration of H₃0⁺ in solution; the pH sclae is a compact way to specify the acidity of solutions
pH =…?
-log[H₃0⁺]
In general at 25ºC if pH is less than 7 the solution is ____.
acidic
In general at 25ºC if pH is greater than 7 the solution is ____.
basic
In general at 25ºC if pH is equal than 7 the solution is ____.
neutral
pOH=…?
-log[OH⁻]
On the pOH scale a pOH of less than 7 is ___ and pOH of greater than 7 is _____.
basic
acidic
pH + pOH = …? (at 25ºC)
14.00
The pKa of a weak acid is another way to quantify its _____.
strength
The smaller the value of pKa, the _____ the acid.
stronger
pKa = …?
-log Ka
Why can the autoionization of water be ignored in most strong acid and weak acid solutions?
Because the autoionization of water produces even less H₃0⁺ than in pure water
The concentration of H₃0⁺ in a strong acid solution is simply equal to the concentration of the ____ ____
strong acid
Define percent ionization
The concentration of ionized acid in a solution divided by the initial concentration of acid, multiplied by 100%.
The equilibrium H₃0⁺ concentration of a weak acid ___ with increasing initial concentration of acid.
increases
The percent ionization of a weak acid ____ with increasing concentration of the acid .
decreases
In general an anion that is the conjugate base of a weak acid is itself a ____ ____.
weak base
In general an anion that is the conjugate base of a strong acid is ____-____.
pH-neutral
Ka x Kb = …?
Kw
Anions can act as weak ____.
Bases
Cations can act as weak ____.
Acids
What are the three main categories cations can be divided into?
- Cations that are the counterions of strong bases
- Cations that are the conjugate acids of weak bases
- Cations that are small, highly charged metals.
Why Is HF a weak acid?
Because the F- ion has a significant affinity for H+ ions and so when F- is in water it takes the H+ off the water (acts as a weak base).
Strong bases generally contain ____ ions and a _____
hydroxide
counterion
Do counterions (from a strong base) interact with water? How?
Yes through ion-dipole forces, but THEY DO NOT IONIZE WATER and therefore they do not contribute to the acidity or basicity of the solution
In general cations that are counterions of strong bases are themselves ____ _____
pH neutral
In general, a cation that is a conjugate acid of a weak base is a weak ____
acid
Small highly charged metal cations form weakly ____- solutions
acidic
Salts in which neither the cation nor the anion acts as a base or an acid form ____ ____ solutions
pH neutral
Salts in which the cation does not act as an acid and the anion acts as a base form ____ solutions
basic
Salts in which the cation acts as an acid and the anion does not act as a base form ____ solutions
acidic
Salts in which the cation acts as an acid and the anion acts as a base form solutions in which the pH depends on the relative strengths of the ____ and the _____
acid
base
