practicals Flashcards
1
Q
whymay percentage yeild be low?
A
reaction does not undergo completion
loss of solid in transfer between aparatus
2
Q
what kind of filtration shjould you use in recrystilisation and why?
A
vaccuum filtration so that the solution remains hot
3
Q
how can you dry a solid?
A
in an oven at lower temperature to its melting point
4
Q
how do you calibrate a pH meter?
A
use 2 buffer solutions of known pH
5
Q
Why might titration values get bigger?
A
they did not mix the orginal solution properly so higher concentration at the bottom
6
Q
why do you add anti bumping granuals?
A
to allow the liquid to boil more gently
7
Q
what is meant by heating under reflux?
A
boiling a mixture
condensing the vapour to return it to the flask
