Chapter 16 - Acid-Base Equilibria Flashcards
Properties of acidic solutions are due to what?
H+(aq) ions
Properties of basic solutions are due to what?
OH-(aq) ions
What is an H+ ion?
It is simply a proton with no surrounding valence electrons.
What is a hydronium ion and what is it used for?
H3O+(aq) and it is often used to represent the
predominant form of H+ in water instead of the simpler H+(aq).
What is a Bronsted-Lowry acid?
A substance that donates a proton to another substance.
What is a Bronsted-Lowry base?
A substance that accepts a proton from another substance.
When is a substance amphiprotic?
When it can act as either a Bronsted-Lowry base or acid
What is the conjugate acid of the base?
When a proton is added to the base.
What is the conjugate base of the acid?
When a proton is removed from the acid.
What is a conjugate acid-base pair?
When an acid and its conjugate base (or a base and its conjugate acid) are combined.
What is autoionization of water?
Two water molecules produce a hydronium ion and a hydroxide ion by transfer of a proton.
(H₂O + H₂O ⇌ H₃O⁺ + OH⁻)
What is the ion-product constant for water?
Kw=[H+][OH-]=1.0x10^-14 at 25°C.
What is pH (it’s a formula)?
pH=-log[H+]
At 25°C, what are the pH levels of neutral, acidic, and basic solutions, respectively?
Neutral pH=7.00
Acidic pH=less than 7
Basic pH=more than 7
What’s pOH (it’s a formula)?
pOH=-log[OH-]
How is the relationship between pH and pOH calculated?
pH+pOH=14.00
What are strong acids?
They are strong electrolytes that ionize completely in aqueous solution.
What are the 7 most common strong acids?
- HCl
- HBr
- HI
- HNO3
- HClO3
- HClO4
- H2SO4
What are two common strong bases?
- Ionic hydroxides of the alkali metals
2. Heavy alkaline earth metals
What are weak acids?
A weak acid (AKA weak electrolyte) is an acid that is partially dissociated in an aqueous solution.
What is the acid-dissociation constant (Ka) equal to?
It’s equal to the equilibrium constant ([Products]/[Reactants]).
The larger the value of Ka, ___?
The stronger the acid.
What are polyprotic acids?
Acids that have more than one ionizable proton (ex: H3PO4).
Why do the acid-dissociation constants of polyprotic acids decrease in the order Ka1>Ka2>Ka3?
Because nearly all the H+ in a polyprotic acid comes from the first dissociation step (meaning not much H+ is left after the first step).
How is the relationship between Ka and Kb expressed and what does it mean?
Ka*Kb=Kw.
The acid-dissociation constant of an acid and the base-dissociation constant of its conjugate base equals Kw.
What is hydrolysis?
Hydrolysis is a chemical reaction in which H2O is split into H+ and OH- and combines with and combines with the cations and anions of a chemical compound.
What are oxyacids?
Acids in which OH groups are bound to a central atom.
What is a Lewis acid?
An electron-pair acceptor.
What is a Lewis base?
An electron-pair donator.
What are carboxylic acids?
Organic acids containing the COOH group.
