EL - Acids Flashcards
1
Q
what is the Brønsted-Lowry definition of an acid?
A
they are proton donating atoms
2
Q
what is the Brønsted-Lowry definition of a base?
A
they are proton accepting atoms
3
Q
how do bases neutralise acids?
A
by soaking up the H+
4
Q
what is an alkali?
base or acid
A
they are soluble bases that relase OH- ions in aq solutions
5
Q
what happens during a neutralisation reaction?
A
a salt is formed when H+ of an acid is replaced by metal ion or ammonium ion
acid + carbonate —> salt + water = effervessemce due to CO2 gas evolved and solid carbonate dissolved
6
Q
what is the method to a titration?
A
- rinse equipment with distilled water
- pipette 25cm3 of alkali into a conical flask
- add acid solution to burette ensuring jet space is filled
- add few drops of indicator
- use white tyle underneith so colour change is. more onbservable
- add acid to alkali drop wise at end point whilst swirling
- note burette readings (before and after)
- repeat titrations until at least 2 concordant results obtained (within 0.1 of eachother)
7
Q
what are the safety precautions of a titrations?
A
- acids and alkalis atre corrosive and at low concs acids are irritant
- wear eye protection and gloves
8
Q
accuracy and titirations:
A
- if jet space is not filled = higer titre reading then expected
- concical flask instead of beaker = easier to swirl
- indicatord generally weak acids = only add few drops otherwise results will be effected
9
Q
how do you calculate % uncertaincy?
A
= uncertaincy / measurement made on apparatus
x ans by 100
