Acids And Bases Flashcards
What is a Brønsted-Lowry base?
Proton (H+) acceptor
What is a Brønsted-Lowry acid
Proton (H+) donor
HCl
What is a Lewis acid?
Electron pair acceptor
NH3
What is a Lewis base?
Electron pair donor
Cu2+
Are all Brønsted-Lowry acids Lewis acids?
Yes
Lewis acids do not have proton transfer
Litmus in acid and alkali
Acid - pink
Alkali-blue
Methyl orange color in acid and base
Acid-red
Alkali-yellow
Phenolphthalein colour in acids and alkali
Acid-colourless
Alkali-pink
What is a base?
Substance that accepts H+
Metal oxides/hydroxides
Ammonia
Soluble carbonates/ hydrogen carbonates
What is an alkali ?
Alkalis form OH- ions
Acid + metal –>
Acid + metal –> salt + hydrogen
Acid + base –>
Acid + vase –> salt + water
Neutralization reaction
Acid + carbonate –>
Acid + carbonate –> salt + water + carbon dioxide
How to distinguish between strong and weak acids and bases
3 ways
Electrical conductivity
Strong high
Rate of reaction
pH
Weak acids
Ethanoic (organic)
Carbonic (H2CO3)
Phosphoric (H3PO4)
Strong acids
Hydrochloric
Nitric (HNO3)
Sulfuric
Strong bases
Li/Na/K/Ba hydroxide
Weak acids
Ammonia
Ethylamine
How difference between strong and weak acids?
Strong acids/bases- almost complete dissociation in solution
Weak-partially dissociate in solution
What is a change in 1 pH in H+?
X10
pH =
pH= - log [H+]
H+ = 10^-pH
What is Kw?
Ionic product constant of water
Kc [H2O] = [ H+] [OH-]
What affects KW?
Temperature dependent (equilibrium constant)
Increase temperature increases kW
- more dissociation
- endothermic
Find H+ of pure water
H+ = square root KW
At 25c
Find pOH knowing pH
pH + pOH = 14
Find pH from pKw
pH + pOH = pKw
What is Ka?
Ka = [H3O+] [A-] / [HA]
Concentration of ions/ dissociation
-acid dissociation constant
What affects Ka?
- temperature
- acid
What is Kb?
Kb = [BH+] [OH-] / [B]
Base dissociation constant
What is a larger pKa?
Weaker acid
Relationship between acid and conjugate base
Strong acid = weak conjugate base
Organize acid strong to weak:
B&j jhhhh
What is a buffer solution?
Resistant to change in pH
When adding a Small amounts if acid/alkali
Composition of acidic buffers
Weak acid (ch3cooh)
Salt of weak acid+strong alkali (Nach3coo)
Fully Dissociates to CH3COO-
What happens in acidic buffer adding H+
Reacts with base
H+ + CH3COO- CH3COOH
What happens add OH- in acidic buffer?
OH- reacts with acid
CH3COOH + OH- CH3COO- + H2O
Composition of basic buffer?
Weak base (NH3)
Salt of weak base+strong acid (NH4Cl)
Fully dissociates to NH4+
Determine pH of buddy solution
Bffbdbgddb
Find pH
pH =pKa + log[salt]/[acid]
In buffer when does pH=pKa and pOH=pKb
[acid]=[salt]
[base]=[salt]
How to make buffer
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Factors affect buffers
Temperature - change Ka/ kb, changes pH
Not dilution- not change pH but buffer capacity
What is the equivalence point ?
In titration
Stoichiometrically equivalent amount avid and base
Salt and water only
Strong acid and base
Equivalence - 7
Initial pH 1
PH changes gradually to equivalence
Ph jump 3-11 at equivalence
Curve flattens at high pH
Weak acid strong base
Equivalence - >7
Initial pH girly high 3
Stays constant until equivalence
Jump form 7-11 at equivalence
Curve flattens at high pH 13