Thanyha Kirisanker
Unit 2: Practical scientific procedures and techniques
Concentrate on keeping up your standards.
I am a newly appointed technical assistant at a large chemical plant, Chemcalequip. I will be making
and testing standard solutions using titration and colorimetry procedures. I will evidence all my
practical skills along with my results and calculations and the evaluation of the techniques and
possible improvements. Before, I start with making my standard solution with Sodium Hydroxide, I
am going to assess the health and safety for the chemicals and calibrate my equipment for my
standard solution.
Calibration
Before I carry out the practical, I will calibrate the following equipment which are the pH meter,
balance, Volumetric flask, Pipette, Burette. To calibrate the pH meter, I stirred the pH meter in
distilled water to rinse it for any residue and then used my sodium carbonate as a buffer solution to
take the reading, it said 9.4 on the pH meter and then I rinsed it again in distilled water and put it in
distilled water to take a reading and it read 7 which is neutral. This shows that pH meter was
calibrated properly, and it was very accurate.
NaOH pH meter reading 9.4
Distilled water pH meter reading 7
The balance must be calibrated before preparing the solution. To calibrate a balance, you use a
range of weights which are 0.1g, 1.0g, 10g, and 100g and place them one at a time onto the balance
that has been set to 0. If the reading shown on the balance is not true to the measurement of the
weight, then the balance is not accurate and should not be used in the experiment. When we
calibrated the equipment the balance calibration was out by 0.03g.
To calibrate a volumetric flask can be calibrated by weighing it empty and then weighing it filled to
the mark with distilled water.
Health and Safety
Before carrying out the practical you will need to clear your area which you are using to carry out the
experiment, tuck your bags away and tie up your hair if you have long hair. You will need to wear
goggles when working with chemicals like sodium hydroxide as they are an irritant to the skin and
eyes. You could also wear gloves when working with sodium hydroxide as it is an irritant to the skin
and eyes. If the solution we are using contains up to 50% concentration of sodium hydroxide, it is
safe to use a nitrile glove. If any acid or base should spill on skin or clothes flush the area
immediately with copious amounts of water. (CLEAPPS, 2021)
Works Cited
CLEAPPS, 2021: , (CLEAPPS, 2021),
Making Sodium Hydroxide
A standard solution is a solution containing a precisely known concentration of an element or a
substance. A known weight of solute is dissolved in solvent to make a specific volume.
, Thanyha Kirisanker
Unit 2: Practical scientific procedures and techniques
Standardisation is the process of determining the exact concentration also known as molarity of a
solution. Before starting the practical we must make sure the balance, measuring cylinder and
pipette is calibrated. Calibration of a scientific instrument helps to maintain accuracy of that
instrument. The process involves using the instrument with known values. This helps the instrument
to produces results that are more accurate.
Apparatus list
Graduated volumetric flask with stopper- 250ml
Funnel
Pippete
100ml beaker
Weighing boat
Distilled water
Balance
Sodium Hydroxide
Spatula
100ml measuring cylinder.
Method
Firstly, we started by calibrating the balance, we did this by switching it on, once it was level and
then we put a weighing boat on top of the balance and turned it off and then back on to ensure
that all the measurements were accurate.
Set a rough balance to zero with a weighing boat on it.
Add about 3g of sodium hydroxide to the weighing boat.
Set the balance to zero with nothing on it and reweigh the boat plus the sodium
hydroxide.
Accurately, find the weight of the boat and sodium hydroxide
Tip the contents of the bottle into a 250 cm 3 standard flask through a glass funnel.
Reweigh the weighing bottle and calculate the accurate mass transferred to the flask.
Add about 100 cm3 of distilled water to the flask. Dissolve the sodium hydroxide and
then make up to the mark with distilled water. Use a dropping pipette when you are
getting near to the mark.
Calculation
Mr of NaOH- 49
0.75 x 0.1dm3 = 0.075
0.075 x 49 = 3.675/ 3g
Health and Safety
Sodium hydroxide is an irritant to the skin and eyes. To prevent anything from happening you should
wear eye protection, including when making or disposing solutions. Wear protective gloves if the
concentrated solution is handled in more than tiny amounts. Wash exposed skin thoroughly after
handling the sodium hydroxide.
Evaluation
Unit 2: Practical scientific procedures and techniques
Concentrate on keeping up your standards.
I am a newly appointed technical assistant at a large chemical plant, Chemcalequip. I will be making
and testing standard solutions using titration and colorimetry procedures. I will evidence all my
practical skills along with my results and calculations and the evaluation of the techniques and
possible improvements. Before, I start with making my standard solution with Sodium Hydroxide, I
am going to assess the health and safety for the chemicals and calibrate my equipment for my
standard solution.
Calibration
Before I carry out the practical, I will calibrate the following equipment which are the pH meter,
balance, Volumetric flask, Pipette, Burette. To calibrate the pH meter, I stirred the pH meter in
distilled water to rinse it for any residue and then used my sodium carbonate as a buffer solution to
take the reading, it said 9.4 on the pH meter and then I rinsed it again in distilled water and put it in
distilled water to take a reading and it read 7 which is neutral. This shows that pH meter was
calibrated properly, and it was very accurate.
NaOH pH meter reading 9.4
Distilled water pH meter reading 7
The balance must be calibrated before preparing the solution. To calibrate a balance, you use a
range of weights which are 0.1g, 1.0g, 10g, and 100g and place them one at a time onto the balance
that has been set to 0. If the reading shown on the balance is not true to the measurement of the
weight, then the balance is not accurate and should not be used in the experiment. When we
calibrated the equipment the balance calibration was out by 0.03g.
To calibrate a volumetric flask can be calibrated by weighing it empty and then weighing it filled to
the mark with distilled water.
Health and Safety
Before carrying out the practical you will need to clear your area which you are using to carry out the
experiment, tuck your bags away and tie up your hair if you have long hair. You will need to wear
goggles when working with chemicals like sodium hydroxide as they are an irritant to the skin and
eyes. You could also wear gloves when working with sodium hydroxide as it is an irritant to the skin
and eyes. If the solution we are using contains up to 50% concentration of sodium hydroxide, it is
safe to use a nitrile glove. If any acid or base should spill on skin or clothes flush the area
immediately with copious amounts of water. (CLEAPPS, 2021)
Works Cited
CLEAPPS, 2021: , (CLEAPPS, 2021),
Making Sodium Hydroxide
A standard solution is a solution containing a precisely known concentration of an element or a
substance. A known weight of solute is dissolved in solvent to make a specific volume.
, Thanyha Kirisanker
Unit 2: Practical scientific procedures and techniques
Standardisation is the process of determining the exact concentration also known as molarity of a
solution. Before starting the practical we must make sure the balance, measuring cylinder and
pipette is calibrated. Calibration of a scientific instrument helps to maintain accuracy of that
instrument. The process involves using the instrument with known values. This helps the instrument
to produces results that are more accurate.
Apparatus list
Graduated volumetric flask with stopper- 250ml
Funnel
Pippete
100ml beaker
Weighing boat
Distilled water
Balance
Sodium Hydroxide
Spatula
100ml measuring cylinder.
Method
Firstly, we started by calibrating the balance, we did this by switching it on, once it was level and
then we put a weighing boat on top of the balance and turned it off and then back on to ensure
that all the measurements were accurate.
Set a rough balance to zero with a weighing boat on it.
Add about 3g of sodium hydroxide to the weighing boat.
Set the balance to zero with nothing on it and reweigh the boat plus the sodium
hydroxide.
Accurately, find the weight of the boat and sodium hydroxide
Tip the contents of the bottle into a 250 cm 3 standard flask through a glass funnel.
Reweigh the weighing bottle and calculate the accurate mass transferred to the flask.
Add about 100 cm3 of distilled water to the flask. Dissolve the sodium hydroxide and
then make up to the mark with distilled water. Use a dropping pipette when you are
getting near to the mark.
Calculation
Mr of NaOH- 49
0.75 x 0.1dm3 = 0.075
0.075 x 49 = 3.675/ 3g
Health and Safety
Sodium hydroxide is an irritant to the skin and eyes. To prevent anything from happening you should
wear eye protection, including when making or disposing solutions. Wear protective gloves if the
concentrated solution is handled in more than tiny amounts. Wash exposed skin thoroughly after
handling the sodium hydroxide.
Evaluation
