8. Acids and bases Flashcards
Differentiate between Lewis, Bronsted Lowry and Arhenius acid base thoeries
LEWIS - e involved (acid - acceptor, base - donor) AA, BD
BRONSTED - LOWRY - H+ involved (acid - H+ donor, base - H+acceptor) AD, BA
ARRHENIUS - H+/OH- (acid - donates H+, base - donates OH-)
AABDABA (Lewis, Bronsted Lowry)
Define amphiprotic and amphoteric
AMPHIPROTIC - chemical species which can both accept and donate H+ - both Bronsted Lowry base and acid (HCO3-) (smaller group - amphiprotic are amphoteric)
AMPHOTERIC - chemical species which can be both an acid and a base (larger group) ex: Al2O3
Acid properties
- corrode metals
- neutralisation with bases and metal oxides
- reactions with xCO3 , xHCO3
- reactions with metals above H in reactivity series
- reactions with indicators
C Base MeO indic CO AbH
Base properties
- bitter, soapy
- alkaline = base soluble in H2O
- neutralisation with acids
- displacement of ammonia from ammonium salts: NH4Cl + NaOH -> NaCl + NH3 + H2O
- reactions with indicators
So Bit Alk Acids DisplAmm Indic
Name strong and weak acids
STRONG: HCl, H2SO4, HNO3
WEAK: CH3COOH, H2CO3 (organic)
Name strong and weak bases
STRONG: group 1, 2 hydrox, Ba(OH)2
WEAK: NH3, C2H5NH2
Examples of acid rain formation
- Sulphur (combustion):
1) S+O2 -> SO2
2) SO2+H2O -> H2SO3 (dissolves and reacts)
2SO2+O2 -> 2SO3 )photochemical oxidation in atmosphere)
3) SO3+H2O -> H2SO4
- Nitrogen (vehicle engines):
1) N2+O2 -> 2NO. -> 2NO.+O2 -> 2NO2
2) 2NO2+H2O -> HNO2 + HNO3 (dissolves and reacts)
3) NO2+SO2 -> SO3+NO
2NO+O2 -> 2NO2
What are the environmental effects of acid deposition (rains)
- pH of lakes/rivers changes -> harms organisms
- afects availability of metal ions in soil - forms insoluble forms
- plants
- biuldings + statues etc
- human health
Whta is the temperature effect on water ionistaion
As temperature rises, forward reaction is favoured -> more ions -> Kw increases
Water dissociation is endothermic
Uses of Kw
Ka x Kb = Kw = 1x10-14
pKa x pKb = pKw (-logKa=pKa)
What is the Henderson Hasselback equation?
Define buffer and explain its action principal
Buffer - aq solution whose pH remains unchanged when it is diluted with H2O or when elatively small amount of acid / base is added (RESISTS pH CHANGE)
Weak acid / base and its salt (prepared by 2:1 acid + base or vice versa)
How do salt complexes hydrolyse?
Salt complexes hydrolyse into acidic solutions
How is a reaction called which gives off bubbles
Effervescence - ex acids with metals
State colours in acid and base of litmus, methylorange and phenolphthalein
What are the relationships between Ka, pKa, Kb and pKb in strong / weak acids /bases
What is the relationship between acid / base and its conjugate acid /base?
What are the possible titration curves for strong / weak acids / bases?
An example of a lweis acid and base reaction
- BF3 and NH3 reaction
- when ligands bind to a central ion to form a complex ion - ligands are Lewis B, centra ion Lewis A
