Unit 8 Acids and Bases Flashcards
What is a bronsted Lowry acid?
a substance that gives hydrogen atom known as a proton donor
What is a bronsted Lowry base?
substance that receives hydrogen called proton acceptor
Do acids have a plus or minus sign?
plus sign
Do bases have a plus of minus sign?
minus sign
How do you identify Conjugate acid-base pairs?
- Identify two elements that look similar and underline them
- Identify the acid and the base, the acid usually has an H in the front, the base will have a minus sign
What does Acid dissociation as an equilibrium mean?
when the concentration of an acid and its conjugate base does not change because the forward and reverse reactions are happening at the same rate
What is the Ka expression used for?
reaction of acid in the solvent-base water
What is the format of the Ka expression?
ka=[H3O+][A-]\HA
What is Ka?
the extent to which an acid dissociates in a solution
How is acid strength associated with Ka?
A stronger acid will give a larger Ka value
What is Kb?
the extent of ionization of a weak base
How are base strength and Kb related?
the stronger the base, the stronger the Kb value
What does it mean by water is amphiprotic?
can accept and donate protons
Describe the chemical equation of autoionization.
two waters as reactants make an hydronium and a hydroxide
what is the kw expression?
Kw=[H3O+][OH-]=(1.0 x 10-7)(1.0 x 10-7) = 1.0 x 10-14
What is the Kw value?
1.0 x 10-14
What is a strong acid?
an acid that fully dissociates in water
What is the condition of ka value of a strong acid?
must be greater than 1
What is a weak acid?
acid that does not dissociate much in water
What is the condition of ka value of a weak acid?
must be less than 1
what is the generic formula for ka?
Ka=[H3O+][A-]/[HA]
What is the generic formula for Kb?
Kb=[OH-][BH+][B]
How are Ka and Kb related in terms of proportionality?
Ka and Kb are inversely proportional
what happens to the reaction when the base concentration is deficient?
the reaction will not proceed, not considered a base anymore
What is the conjugate of a strong acid?
weak base
What is the congugate of a weak acid?
a strong base
What is the congugate of a weak base?
strong acid
What is the congugate of a strong base?
weak acid
what is the strategy to solve this Problem: If equal concentrations of reactants and products were mixed, in which direction would the reaction proceed?
Strategy: figure out which side has the strongest acid. the reaction will move the opposite side of where the strong acid is
How does polarity affect acid strength?
The more polar and acid is the stronger it is
what are the trends of increased electronegativity of the periodic table?
the left to right and from bottom to top
how does atom size affect acid strength?
the bigger the element the hydrogen atom is connected to, the more polar the bond will be and the more the acid will dissociate
what does the degree of polarity depend on?
the electronegativity of the element the hydrogen atom is bonded to
How does the number of oxygens affect acidity strength? why?
Acidity increases with the number of oxygen atoms because it is very electronegative
When OH is bonded to another element called y, how does the electronegativity of y affect the acidity of the acid?
When OH is bonded to another element call it y, the more electronegative y is, the more acidic the acid will be
What is the formula for the pH?
ph=-log[H+]
What is the formula for the pOH?
pOH=-log[OH-]
If I rearrange the pH scale formula for H+ what will it look like?
[H+]=10-ph
If I rearrange the pOH scale formula for OH- what will it look like?
[OH-]=10-pOH
what is pH
the measure of acidity
what is the pH of the neutral solution?
7
what is the pH Acidic solution?
less than 7
what is the pH of a Basic solution?
has a pH greater than 7
what is the formula to find pH or pOH given the value of one?
14=pH+pOH
is the solution an acid or base with pOH is less than 7
a base
is the solution an acid or base with pOH is greater than 7
an acid
What is the formula to find the pKa?
pka=-log(Ka)
What is the formula to find the pKb?
pkb=-log(kb)
What is the relationship between acid strength and pKa?
Stronger acids give a negative or lower pKa
What is the Leveling affect?
Any two strong acids will differ in acid strength, but in water, they will exhibit the same acid strength as hydronium. Same for base, instead they will inhibit the same strength as hydroxide
What is the formula to find the kb given pkb?
kb=10^-pkb
What is the formula to find the pkb?
pkb=-log(kb)
What do ions of weak acids reacting with water to form?
Ions of weak acids react with water to form OH-
What is salt (ionic compounds) hydrolysis?
when the ion reacts with water. The water molecule splits into H+ and OH-
What do ions of strong acids react with water to form?
Ions of strong acids and bases do not influence pH
What do ions of strong bases react with water to form?
Ions of strong acids and bases do not influence pH
What are poor enough acids and bases considered?
they are not considered acids or bases at all
Will a salt derived from a strong acid and weak base will be acidic or basic? Explain
A salt derived from a strong acid and weak base will be acidic due to the presence of strong acid because there are more hydronium than hydroxide ions
If ka>kb what is the pH and the strength of the acid and the base?
pH<7 acid stronger than base
If Ka<kb what is the pH and the strength of the acid and the base?
Ka<kb>7 base stronger than acid</kb>
If Ka=KB, what is the pH and the strength of the acid and the base?
Ka=KB then pH~7
what is the relationship between Ka and Kb?
they are inversely proportional
