acids Flashcards
why is water neutral at 50 degrees
[H] = [OH]
how does temp affect Kw
as temp increases, Kw also increases. as temp increases, equilibrium shifts to the right to oppose temp increase and dissociation increases. dissociation of water is endothermic
why water conc is not seen in Kw expression
water is constant
why are ph values different
one is strong acid and other is weak acid
why must mixture be acidified so crystals can appear
acid reacts with carboxyalte
when volume increases of buffer solutions,
pH is the same
ratio/proportion [HA]/[A-]is the same
what happens when carbonate reacts with acid and why
H+ reacts with carbonate
equilibrium shifts to the right
buffer solution defintion
minimises pH changes
on addition of SMALL amounts of acid or alkali
why buffer solution forms
acid is in excess/some acid remains
strength of an acid meaning
proportion of dissociation
How can aqueous solution of acid contain hydroxide ions?
Water dissociates
How does this buffer control pH?
Added alkali reacts with H+ so equilibrium shifts to the right
O- reacts with added acid so equilibrium shifts to the left
How can student measure pH continuously
Use pH meter
Suggest why salts of aspirin are more soluble than aspirin in water ?
Salts are ionic and attracted to polar water
Explain why swallowing soluble aspirin may lead to irritation of the stomach lining?
COO- reacts with H+ forming COOH
aspirin precipitates out
What important factor does the student need to consider when deciding on the most
suitable indicator to use for this titration?
Vertical section matches the (pH) range (of the
indicator)
