CHM-6 Acids and Bases Flashcards
What is an acid?
A proton (hydrogen ion) donor.
What is the acid dissociation constant?
Quantifies the extent of dissociation of a weak acid.
- High constant = Stronger Acid
- Low constant = Weaker acid
Equation to calculate Acid Dissociation Constant.
Ka = [Product 1 + Product 2]/Acid
Describe how an acid dissolves in water.
A proton (hydrogen ion) is transferred to water to produce a hydronium ion and a negative ion, depending on the acid.
An acid which is 100% ionised in solution is a…
Strong acid
What would the reaction of HCl and water look like?
HCl + H20 ---> H3O+ + Cl- or HCl ---> H+ Cl- or Hydrogen Chloride + Water ---> Hydronium + Chloride ions
Equation to calculate pH.
pH = -log10 [H+]
What is a weak acid?
An acid that doesn’t ionise fully when dissolved in water
What is pKa?
A way of interpreting the Ka equilibrium without scientific notation
How to calculate pKa?
pKa = -log10 Ka
What are the two varieties of acid?
Binary Acids - Composed of hydrogen and a nonmetal
Oxyacids - Composed with covalent bonds in this fashion: H-O-X. Where X is a given element.
Oxyacids with……are more acidic.
More oxygen atoms bonded to the central atom
How would a diprotic (two protons) reaction look?
Ka1 = Etc….
+
Ka2=Etc….
Two different equilibrium constants for each proton produced.
How would you calculate the equilibrium constant for a base?
Kb = [Product 1+ + Product 2-]/Base (OH-)
Which bases are strongest?
Hydroxides of group 1A Metals
What is a conjugate Acid-Base Pair?
2 species that are related by 1 H+ (Proton)
E.g H2O and H3O+ have a difference of H+
A Strong acid has a……conjugated base
Weak (And vice versa)
What is the ion product constant for water?
Kw = [H+]+[OH-] = 1.0 x 10/-14
How is the H+ value from the acid dissociation found?
Using the “ICE Method”
What does ICE stand for?
INITIAL Acid [H+] concentration
CHANGE in acid [H+] concentration
Acid [H+] concentration at EQUILIBRIUM
(Concentration is known as ‘x’)
What is a salt? (4 Points)
Ionic compound
The anion isn’t OH- or O2-
The cation isn’t H+
Composed of cation and anion
Which reaction do an acid and base form salt and water?
Neutralisation Reaction
What is salt hydrolysis?
When a salt reacts with water to give an acid or base.
The weaker the conjugate acid…
the stronger the conjugate base
What is a buffer?
A solution that resists pH changewhen a small amount of acid or base is added or when a solution is diluted.
What does a buffer consist of?
A mixture of a weak acid and its salt
or
A mixture of a weak base and its salt.
The range in which a buffer maintains it’s pH is known as the…
Buffering Capacity
The Henderson-Hasselback equation
pH = pKa -log ([Salt]/[Acid])
What is an amphoteric substance?
One that can act as either an acid or a base, such as water
What happens after the equivalent point when a Weak acid reacts with a strong base?
The curve follows the pattern of a strong acid, rather than a weak one.
