Acids and bases Flashcards
What happens to the remainder on the product side of an acid gives away a proton?
it is a base
What are characteristics of strong acids and bases?
React 100%
Value of x is the size of initial concentration
Value of K is large
Equilibrium favours the product side so much there is effectively no reactant remaining, irreversible reaction
What are characteristics of weak acids and bases?
React less than 100%
X is relatively small
K value is smaller than 1
Equilibrium favours reactant side and there is a measurable amount of product
The larger the K value, the stronger the acid or base
Have a range of strengths based on their K values
Do strong acids have full, partial, or no ionization?
full
Do weak acids have full, partial, or no ionization?
partial because they have a measurable amount of product
Do very weak a ids have full, partial, or no ionization?
none because the lower the K value, the less HA reacts
The stronger the acid…
the weaker its conjugate base
The weaker the acid…
the stronger its conjugate base
The stronger the base…
the weaker the conjugate acid
The weaker the base…
the stronger its conjugate acid
What are middle strength acids and bases?
not super strong or super weak,
they can sometimes donate and accept electrons
Are very weak acids and bases spectator ions?
yes
What is the autoionization of water?
water can undergo a reaction with itself
What does it mean when water is amphoteric?
it can be both an acid or a base
What is the value of Kw?
Kw = [H3O][OH] = 1.0x10-14 at 25 degrees celsius
Are H3O and OH directly or inversely proportional?
inversely
If H3O concentration goes up, OH concentration goes down because they are equal to a constant number
Do acidic solutions have more H3O or OH?
H3O
Do basic solutions have more H3O or OH?
OH
What is the pH equation?
pH=-log[H3O+]
What is the pOH equation?
pOH=-log[OH-]
Is there any excess H3O or OH when the pH is neutral?
no
What kind of acid is it when Ka<1?
weak
What kind of acid is it when Ka>1?
strong
What kind of base is it when Kb<1?
weak base
What kind of base is it when Kb>1?
strong
What happens to the base when it steal protons?
turns into its conjugate acid and forms OH
Are the Ka and Kb of weak acids and bases related to Kw for a conjugate acid-base pair?
yes
What is the Kw equation?
Ka x Kb = Kw
What is the value of Kw?
1.0 x 10^-14
What do salts contain?
either a weak acid or a weak base as the cation or anion
What is the pH of acidic salt?
less than 7
Do medium strength acids and bases have a Ka and a Kb?
yes
What are the strong acids?
HClO4, HI, HBr, HCl, H2SO4, HNO3, HClO3
What are the strong bases?
LiOH, NaOH, KOH, RbOH, CsOH, Ba(OH)2, Sr(OH)2, Ca(OH)2
Do conjugate bases of strong acids have base strength?
no
What are the conjugate bases of strong acids?
Cl, Br, NO3, HSO4, ClDo O4
Do conjugate bases of strong acids accept protons?
no
Do counterions strong bases have acid strength?
no
Do weak conjugate acids of strong bases donate protons?
no
What are the weak conjugate acids of strong bases?
Na, K, Li, Rb, Sr 2+, Ba 2+
What are polyprotic acids?
acids that have more than one acidic proton
What is diprotic?
2 acidic protons
What is triprotic?
3 acidic protons
What is polyprotic?
many acidic protons (used for anything greater than 2)
Are protons donated in successive stages?
yes
What happens to the acid strength of remaining protons after each proton is donated?
decreases
What is the Total [H3O] equal to?
[H3O]+[H3O]+[H3O]+…
What step is the majority of H3O made in?
first step
What is the common ion effect?
how equilibrium is affected when a conjugate product (common ion) is already present in the solution
What are buffer solutions?
solutions that resist pH change when strong acid or base is added
What are buffer solutions made from?
solutions that contain both an acid and a base
How do you create a solution with both an acid and a base?
you use conjugate acid/base pairs of weak acids/bases
What kind of concentration do typic buffer solutions have?
equal concentration of conjugate acids and bases
Do buffer solutions buffer at a specific pH?
yes
Can buffer solutions have a super strong acid or base? Why?
no because their conjugate is too weak
Do buffers resist pH changes?
yes
Is there more or less H3O when the Ka is larger?
more
Is there more or less H3O when the Ka is smaller?
less
What is the relationship in between ratio of weak acid to weak conjugate base and H3O?
direct
What happens to pH when the ratio of [HA]/[A] changes?
H3O changes which changes the pH
What is the Henderson-Hasselbalch equation?
pH = pKa + log[A]/[HA]
What is the pKa the starting point for?
buffer pH
What is the size of pH relative to pKa when [A]> [HA]
pH > pKa
What is the size of pH relative to pKa when [HA] > [A]?
pH < pKa
What are neutralization reactions?
reactions that involve strong acids and bases in which one or the other is neutralized (removed from the solution by complete reaction)
irriversible reactions
What kind of pH do neutralization reactions have?
neutral
What do neutralization reactions make?
salt and water
What happens to the weak acid when H3O is added to a weak acid and a conjugate base?
weak acid gets bigger
What happens to the conjugate base when OH is added to a weak acid and a conjugate base?
conjugate base gets bigger
What is the buffer capacity?
amount of strong acid that can be added to a solution before the pH changes dramatically
What pH rand do buffers have the most buffering capacity in?
in a pH range of pKa ± 1
When do you do ICE charts and MICE charts?
Do ice charts when the reaction is reversible, do mice charts when reaction is irreversible
Mice charts use initial moles
Ice charts use initial molarity
How do you make a buffer solution?
- Adding a salt of the conjugate acid or base to an existing solution of a weak acid or base
-Add roughly the same amount of salt - Partial neutralization of a weak acid or base solution
-Add less than the amount of strong acid/base solution because we want it to be partially neutralized
-You get roughly equal amounts of conjugate acids and bases
How do you choose a pH when making a buffer solution?
Find a list of weak acid pKa values
Choose a weak acid with a pKa +- 1 from your target pH
What is titration used to determine?
concentration of a solution by reacting it with a reagent of known concentration
When are reactants stoichiometrically equivalent?
at the equivalence point
What is the titration equation?
HX + B → BX + H2O
Does pH change as the volume increases?
yes
What is the equivalence point?
the point at which the reactants are stoichiometrically equivalent to each other
-Moles of what you’re adding is the same as (or equivalent to ) what is in the beaker
What is the pH of a strong acid and strong base reaction?
7 because they cancel each other out
What is the end point?
the point at which a visual indicator changes colour
-Colour change occurs when the reaction is complete
