1
Pearson BTEC National Extended Diploma in Applied
Science
Unit 2A: Practical Scientific Procedures and Techniques
Name: Isbat Uddin
ID: 11208069
Learning Aim A: Undertake titration and colourimetry to determine the
concentration of solutions.
Title: Keeping up the standards.
Scenario
I am a newly appointed technical assistant at a large chemical plant, Chemicalequip. In order
to progress in my role and finalise my induction period, I must demonstrate skills in a range
of practical procedures and techniques. My responsibilities include making sure equipment is
calibrated and chemicals are safely inspected. A major aspect of my job will be making and
testing standard solutions using colourimetry and titration. I must demonstrate my ability to
carry out these techniques. Evidence of my practical skills, along with my results,
calculations, evaluation of techniques and possible improvements will need to be submitted
in a report(s).
Introduction
I will investigate the unknown concentration of an unidentified sample in sodium hydroxide
for this assignment. In order to shed light on the concentration of the unknown samples, six
experiments will be performed to investigate the differences between Titration and
Colourimetry as techniques for determining the concentration of an unknown solution.
Standardising a solution is the process of determining the precise concentration (or strength)
of a chemical solution. It is important to do this because sometimes we are only able to
accurately determine the concentration of a solution we make in the lab - especially if the
chemical is impure or absorbs water from the air. To standardise a solution, we react it with a
primary standard - a substance that is extremely pure, stable, and has a known formula and
molar mass.
As part of the standardisation process, a titration is usually completed. During a titration, one
solution is added slowly to another until a reaction is complete, using an indicator to show
when the end point is reached usually by observing the change in colour. From the volume
of the standard solution we used, along with the concentration of the primary standard we
used, we can calculate the entire concentration of the unknown solution using a balanced
chemical equation.
Standardisation of the solution sodium carbonate (Na 2CO3)
Name: Isbat Uddin ID: 11208069
, 2
Aim: To prepare the 250 cm3 of N/10 standard solution of sodium carbonate.
Hypothesis
It is hypothesised that the prepared sodium carbonate (Na 2CO3) solution can be accurately
standardised using a strong acid such as hydrochloric acid (HCl) through an acid base
titration. The endpoint, indicated by the suitable indicator phenophathelin, will allow precise
determination of the exact molarity of the HCl solution. Since sodium carbonate is stable,
pure and having a known formula mass, it is expected to yield consistent and reliable titration
results with minimal experimental errors.
Calibrations
Calibration is the process of checking and adjusting scientific equipment to ensure it gives
accurate measurements.
We calibrate equipment before an experiment to ensure accurate readings. If equipment is
not calibrated, the measurements may be inaccurate, potentially introducing errors into the
experiment and compromising the validity of the results. Calibration ensures uniformity
among various equipment and enhances the reliability of results.
Pipette
Method to calibrate:
1. Clean the pipette with distilled water to remove contaminants.
2. Set the pipette to the required volume.
3. Weigh a clean, dry container using an electrical balance.
4. Use the pipette to dispense the set volume of distilled water into the
container.
5. Weigh the container again to find the mass of the water dispensed.
6. Convert the mass of water to volume using the density of water.
7. Compare the dispensed volume to the expected volume.
8. Repeat several times and calculate an average to check reliability.
9. If the pipette is inaccurate, adjust or record its error for future use.
Pipettes are designed to measure a certain volume. These are much
more accurate using a measuring cylinder.
Risk Assessment: (for calibration)
● Glass breakage (pipette or beaker) – Handle carefully to avoid cuts, use protective
eyewear.
● Spillage of water on electrical balance – Keep balance area dry and clean spills
immediately.
● Incorrect handling of pipette – Always use pipette filler, never mouth pipette.
Name: Isbat Uddin ID: 11208069
, 3
● Cross-contamination – Ensure pipette is rinsed properly with distilled water.
Balance
Method to calibrate:
1. Ensure the balance is on a stable, level surface and
free from vibration.
2. Switch on the balance.
3. Check that the balance is clean and free from dust
or spilt chemicals.
4. Press the zero button to set the display to 0.000 g.
5. Place a calibration weight on the balance pan.
6. Record the reading shown on the display.
7. Compare the reading to the known mass of the
calibration weight.
8. If the reading differs, adjust according to the
manufacturer’s instructions or record the error.
9. If the calibration has been completed correctly, the display will show “pass” and
return to the weighing screen.
10. Repeat the process with at least two different calibration weights to confirm accuracy
across the range.
11. Record the results and label the balance as calibrated.
Doing calibration this would ensure that the mass you are measuring is correct, ensuring a
higher quality of accuracy.
Risk assessment:
● Electrical hazard – Ensure cables and plugs are not damaged; keep liquids away
from the balance.
● Spillage of chemicals – Only calibrate with clean weights; clean balance immediately
if chemicals spill.
● Heavy or dropped weights – Handle calibration weights carefully to avoid injury or
damage to the balance.
● Glassware near balance – Place glass items carefully to prevent breakage and cuts.
● Incorrect calibration – Always use certified standard weights to ensure accuracy.
Equipment/Chemicals
● Volumetric Flask (250cm3)
● Beaker
● Balance
● Plastic weighing boat
Name: Isbat Uddin ID: 11208069
, 4
● Glass rod
● Na2CO3
● HCl
Health and Safety
● Correct PPE should be worn (laboratory coat, goggles, gloves, closed toe shoe)
● Hair must be tied up and away from the viewing area to prevent distractions during
the experiment.
● Personal belongings must be placed away from the working area.
● Food and beverages should be kept away from the working area.
● Glassware must be handled carefully and be placed away from the work surface.
● Chemicals should be handled with precaution with correct PPE on.
● While weighing, do not spill the substance on the balance pan.
● Funnel should be washed thoroughly several times.
● Shaking of solution should be done carefully so that it may become uniform.
● While making the solution the solvent should be added such that the lower meniscus
of the solvent must be on the mark of the measuring flask.
● Bases are corrosive so they should be handled with care.
Risk assessment
Hazard: Risk: Prevention: Emergency action:
Glassware The glassware may Keep glassware away Immediately seek help
fall and shatter if not from the edge of the from the supervisor.
handled properly. Cut table/counter top, and Rinse wound with
hazard. carry glassware firmly. warm water
Chemicals ● Splash into ● Wear goggles to ● Immediately
(sodium eyes when protect the eyes. wash the
carbonate, pipetting or affected area
hydrochloric pouring ● Wear a with water.
acid) laboratory coat
● Skin and gloves to
irritation/burns protect hands
if spilt on and arms.
hands or
arms.
Name: Isbat Uddin ID: 11208069
Pearson BTEC National Extended Diploma in Applied
Science
Unit 2A: Practical Scientific Procedures and Techniques
Name: Isbat Uddin
ID: 11208069
Learning Aim A: Undertake titration and colourimetry to determine the
concentration of solutions.
Title: Keeping up the standards.
Scenario
I am a newly appointed technical assistant at a large chemical plant, Chemicalequip. In order
to progress in my role and finalise my induction period, I must demonstrate skills in a range
of practical procedures and techniques. My responsibilities include making sure equipment is
calibrated and chemicals are safely inspected. A major aspect of my job will be making and
testing standard solutions using colourimetry and titration. I must demonstrate my ability to
carry out these techniques. Evidence of my practical skills, along with my results,
calculations, evaluation of techniques and possible improvements will need to be submitted
in a report(s).
Introduction
I will investigate the unknown concentration of an unidentified sample in sodium hydroxide
for this assignment. In order to shed light on the concentration of the unknown samples, six
experiments will be performed to investigate the differences between Titration and
Colourimetry as techniques for determining the concentration of an unknown solution.
Standardising a solution is the process of determining the precise concentration (or strength)
of a chemical solution. It is important to do this because sometimes we are only able to
accurately determine the concentration of a solution we make in the lab - especially if the
chemical is impure or absorbs water from the air. To standardise a solution, we react it with a
primary standard - a substance that is extremely pure, stable, and has a known formula and
molar mass.
As part of the standardisation process, a titration is usually completed. During a titration, one
solution is added slowly to another until a reaction is complete, using an indicator to show
when the end point is reached usually by observing the change in colour. From the volume
of the standard solution we used, along with the concentration of the primary standard we
used, we can calculate the entire concentration of the unknown solution using a balanced
chemical equation.
Standardisation of the solution sodium carbonate (Na 2CO3)
Name: Isbat Uddin ID: 11208069
, 2
Aim: To prepare the 250 cm3 of N/10 standard solution of sodium carbonate.
Hypothesis
It is hypothesised that the prepared sodium carbonate (Na 2CO3) solution can be accurately
standardised using a strong acid such as hydrochloric acid (HCl) through an acid base
titration. The endpoint, indicated by the suitable indicator phenophathelin, will allow precise
determination of the exact molarity of the HCl solution. Since sodium carbonate is stable,
pure and having a known formula mass, it is expected to yield consistent and reliable titration
results with minimal experimental errors.
Calibrations
Calibration is the process of checking and adjusting scientific equipment to ensure it gives
accurate measurements.
We calibrate equipment before an experiment to ensure accurate readings. If equipment is
not calibrated, the measurements may be inaccurate, potentially introducing errors into the
experiment and compromising the validity of the results. Calibration ensures uniformity
among various equipment and enhances the reliability of results.
Pipette
Method to calibrate:
1. Clean the pipette with distilled water to remove contaminants.
2. Set the pipette to the required volume.
3. Weigh a clean, dry container using an electrical balance.
4. Use the pipette to dispense the set volume of distilled water into the
container.
5. Weigh the container again to find the mass of the water dispensed.
6. Convert the mass of water to volume using the density of water.
7. Compare the dispensed volume to the expected volume.
8. Repeat several times and calculate an average to check reliability.
9. If the pipette is inaccurate, adjust or record its error for future use.
Pipettes are designed to measure a certain volume. These are much
more accurate using a measuring cylinder.
Risk Assessment: (for calibration)
● Glass breakage (pipette or beaker) – Handle carefully to avoid cuts, use protective
eyewear.
● Spillage of water on electrical balance – Keep balance area dry and clean spills
immediately.
● Incorrect handling of pipette – Always use pipette filler, never mouth pipette.
Name: Isbat Uddin ID: 11208069
, 3
● Cross-contamination – Ensure pipette is rinsed properly with distilled water.
Balance
Method to calibrate:
1. Ensure the balance is on a stable, level surface and
free from vibration.
2. Switch on the balance.
3. Check that the balance is clean and free from dust
or spilt chemicals.
4. Press the zero button to set the display to 0.000 g.
5. Place a calibration weight on the balance pan.
6. Record the reading shown on the display.
7. Compare the reading to the known mass of the
calibration weight.
8. If the reading differs, adjust according to the
manufacturer’s instructions or record the error.
9. If the calibration has been completed correctly, the display will show “pass” and
return to the weighing screen.
10. Repeat the process with at least two different calibration weights to confirm accuracy
across the range.
11. Record the results and label the balance as calibrated.
Doing calibration this would ensure that the mass you are measuring is correct, ensuring a
higher quality of accuracy.
Risk assessment:
● Electrical hazard – Ensure cables and plugs are not damaged; keep liquids away
from the balance.
● Spillage of chemicals – Only calibrate with clean weights; clean balance immediately
if chemicals spill.
● Heavy or dropped weights – Handle calibration weights carefully to avoid injury or
damage to the balance.
● Glassware near balance – Place glass items carefully to prevent breakage and cuts.
● Incorrect calibration – Always use certified standard weights to ensure accuracy.
Equipment/Chemicals
● Volumetric Flask (250cm3)
● Beaker
● Balance
● Plastic weighing boat
Name: Isbat Uddin ID: 11208069
, 4
● Glass rod
● Na2CO3
● HCl
Health and Safety
● Correct PPE should be worn (laboratory coat, goggles, gloves, closed toe shoe)
● Hair must be tied up and away from the viewing area to prevent distractions during
the experiment.
● Personal belongings must be placed away from the working area.
● Food and beverages should be kept away from the working area.
● Glassware must be handled carefully and be placed away from the work surface.
● Chemicals should be handled with precaution with correct PPE on.
● While weighing, do not spill the substance on the balance pan.
● Funnel should be washed thoroughly several times.
● Shaking of solution should be done carefully so that it may become uniform.
● While making the solution the solvent should be added such that the lower meniscus
of the solvent must be on the mark of the measuring flask.
● Bases are corrosive so they should be handled with care.
Risk assessment
Hazard: Risk: Prevention: Emergency action:
Glassware The glassware may Keep glassware away Immediately seek help
fall and shatter if not from the edge of the from the supervisor.
handled properly. Cut table/counter top, and Rinse wound with
hazard. carry glassware firmly. warm water
Chemicals ● Splash into ● Wear goggles to ● Immediately
(sodium eyes when protect the eyes. wash the
carbonate, pipetting or affected area
hydrochloric pouring ● Wear a with water.
acid) laboratory coat
● Skin and gloves to
irritation/burns protect hands
if spilt on and arms.
hands or
arms.
Name: Isbat Uddin ID: 11208069
