Type of chemical analysis to be carried out
The aim of this portfolio was to produce a solution of sodium hydroxide as part of materials to be use in an investigation. The solution of sodium hydroxide was obtained by putting cystals of sodium hydroxide into water, which produced an immediate reaction. This therefor produced a very hot and strong alkaline solution, which was treated with great care.
Safety points
• Safety googles. This was worn during the preparation because sodium hydroxide is caustic and any contact with eye might lead to serious damage to the eye such as clouding of the eye and blindness.
• Gloves. Gloves were worn to prevent contact with the solution. It is very corrosive and can cause burns in all tissues that come in contact with it. The pain sustain can be severe and last for several hours.
• Remain standing at all times during the experiment as unwanted accidents could happen.
• Clear up any other equipment that is not part of the experiment, e.g. bags and books.
• No running around or playing in the laboratory at anytime.
• Avoid and contact with substance.
Materials
• A 100cm3 beaker.
• Sodium hydroxide pellet.
• A weighing boat
• A Glass rod
• Distilled water
• 100cm3 volumetric flask
Method
1) 4g of sodium hydroxide were measured in a weighing boat placed on top pan balance.
2) The sodium hydroxide was then transferred into 100cm3.
3) The weighing boat was rinsed with distilled water, collecting the washing in the beaker.
4) Afterwards it was carefully stirred with a rod.
5)Then this solution was transferred into 100cm3 volumetric flask.
6)Another few cm3 of distilled water was added and then stirred, this way to collect any remaining sodium hydroxide that was left in the beaker.
7)Transferred to a beaker, and was repeated until all the sodium hydroxide had dissolved. The glass rod was rinsed into the beaker with distilled water. This was then transferred into the volumetric flask.
8) The beaker was rinsed a couple of times with a few cm3 of distilled water and the washing was transferred each time into the volumetric flask making sure the total volume did not exceed the 100cm3 mark.
Results
From the experiment I carried out I found out that the PH of my sodium hydroxide solution was 13.6. This results was almost accurate to the solutions used in a laboratory.
Evaluation
During the experiment I encountered some problems in it, the distilled water bottle kept leaking and the PH meter was unstable. The technique provided was simple and easy to understand while the equipment were reliable. The equipment was similar to the ones used in an industrial laboratory and the experiment was also carried out as it would have been if in an industrial laboratory. The error in this experiment, which might have affect the results, is the balance used to measure the sodium hydroxide pellets, as it normally measures 0.0005gram more or less than the actual weight. The Volumetric flask also caused another error, as it was difficult to see the miniscus due to the roughness of the flask. The procedures used to work according to plan apart from the above minor problems. Next time we could improve this experiment by making some little adjustment especially if more time was available.
Vocational implications
Although this experiment is a replica of what happens in industry, it was however on a small scale. This in reality means that there may be adjustment to the protocol if used in an industry. Also an industry will require a greater level of accuracy and sensitivity as the product (e.g. cosmetic products) may cause problems among the customers. This may be achieved by using better scale. Although we used a small scale in
this experiment, an industry has a bigger and better scale, which can measure accurately. Most of the safety measures we undertook during this experiment are also used in an industry but most essentially, a cover dressed called laboratory coat is always worn to safeguard the scientist and his clothing.
