practicals >w< Flashcards
Another student is required to make up 250 cm3 of an aqueous solution that
contains a known mass of MHCO3. The student is provided with a sample bottle
containing the MHCO3.
Describe the method, including apparatus and practical details, that the student
should use to prepare the solution
Stage 1: transfers known mass of solid
a) Weigh the sample bottle containing the solid on a (2 dp)
balance
b) Transfer to beaker* and reweigh sample bottle
c) Record the difference in mass
Stage 2: Dissolves in water
a) Add distilled / deionised water
b) Stir (with a glass rod) or swirl
c) Until all solid has dissolved
Stage 3: Transfer, washing and agitation
a) Transfer to volumetric / graduated flask.
b) With washings
c) Make up to 250cm3 / mark with water
d) Shakes/inverts/mixes
describe how to do titration
- 50 cm of prepared solution in a beaker
- add NaCO3 to rinse burette
-ensure no bubbles - record solution on minisucus
-transfer 25cm into conical flask
-2-3 drops indicator - carry rough titration
errors in titration practical
systematic error - balance
human error - reading the meniscus wrong
to fix: read meniscus on eye level
measurement of enthalpy change
weigh anhydrous copper sulfate
table to record up to 15 minutes
get 25cm of distilled water in polystrene cup and record intial temp
at 4 minute do not record temp
stir the solution until done
plot graph
use graph to determine temp change
