This is an in-depth assignment that describes how to prepare and
standardise solutions for titration and colorimetry, investigate the
concentration of unknown solutions, using procedures and techniques in titration and colorimetry, and skilful applications of procedures and techniques in titrat...
Pearson level 3 BTEC national diploma in forensic and criminal investigation
Unit 2a practical assignment 1
Titration
Part 1 (preparation of a standard solution)
The scale wouldn’t calibrate so we had to estimate the mass of sodium carbonate, so we
the adjusted mass was 1.43g and the non-adjusted weight was 1.21g. We then carefully
transferred the sodium carbonate (Na2CO3) we weighted out, into a beaker. Then added
150ml3 of distilled water to the beaker, and we stirred it until the sodium carbonate had
completely into the distilled water. Then transferred the solution into a 250cm3
volumetric flask, filled up the rest of the flask with more distilled water.
Concentration of our solution= 1.43÷106=0.013mol 0.013×4=0.0052mol/dm 3
Part 2 (standardisation of an acid)
Risk assessment
Action Hazards Control Risk rating Additional
associated with measures Low, med, high action
this action required?
Hydrochloric It could be spilt Make sure to Medium If there is a
acid/methyl on you and keep the lids spillage, make
orange cause irritation on the jars of sure to tell a
or burn the acids, so teacher so it
not to spill can be cleaned
them up
Conical The glass Handle the Medium If the glass
flasks/ could smash glass with breaks, make
burettes and cut care sure to clean it
someone up so no one
gets cut
Calibration of our pipette= 123.47÷5= 24.694
1. 24.64
2. 24.75
3. 24.73
4. 24.72
5. 24.63
We calibrated our pipette using distilled water, and then transferred 25cm3 of our sodium
carbonate solution into a conical flask and added a few drops of methyl orange indicator.
We also cleaned and then the burette up using hydrochloric acid. We titrated the sodium
carbonate solution until the methyl orange indicator turned from orange to pink. We
made a table of results and recorded the measurements of the titre of the hydrochloric
acid. We repeated this over 5 times but didn’t get the most concordant results.
Concentration of hydrochloric acid= 0.025÷1.43= 0.01mol
Part 3a (titration of sodium carbonate with hydrochloric acid, using an indicator)
Risk assessment
Action Hazards Control Risk rating Additional
associated with measures Low, med, high action
this action (Ways of required?
reducing
hazard)
Hydrochloric It could be spilt Make sure to Medium If there is a
acid/methyl on you and keep the lids spillage,
orange cause irritation on the jars of make sure
or burn the acids, so to tell a
not to spill teacher so
them it can be
cleaned up
Conical The glass could Handle the Medium If the glass
flasks/ smash and cut glass with breaks,
burettes someone care make sure
to clean it
up so no
one gets
cut
Calibration of our pipette= 124.16÷5=24.832
1. 24.82
2. 24.86
3. 24.83
4. 24.82
5. 24.83
To start with we calibrated our pipette using distilled water and cleaned and filled up the
burette with hydrochloric acid. Then we carefully transferred 25cm 3 of our sodium
chloride solution into a 250cm3 conical flask and added a few drops of methyl orange
indictor. We titrated the sodium chloride solution with hydrochloric acid until the
indicator turned from orange to pink. We repeated this 5 times, but our results were not
concordant.
Concentration of sodium chloride=58.44x0.025=1.4mol
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