If splashed in eyes:
In case of contact with eyes, rinse immediately with cold water and seek medical advice
If spilt on floor:
Scoop up and clean surface
If spilt on skin or clothing:
Wash off
Hazard sign reads:
Irritating
Method and Materials
- Using a set of scales I weighed out 14.625 grams of sodium chloride on a piece of filter paper
- I then transferred the sodium chloride in to a 250ml beaker.
- I then rinse the filter paper with distilled water to make sure that all the sodium chloride was in the beaker by collecting the washings.
- I then added some distilled water and stirred with a glass rod until the solution was not saturated
- I then transferred the solution into a 250cm³ volumetric flask.
- I then rinsed out the beaker and glass rod into the flask to make sure there was no sodium chloride left in the beaker or on the glass rod.
- I then used the distilled water to top up the volumetric flask until the bottom of the curve of the solution was level with the line. I then took some bodies opinion on whether or not the water was at the right level.
I found the weight of 14.6 grams by adding the relative atomic masses of the two elements together to find the amount needed to make a one mole solution of sodium chloride if mixed with one litre of water. But I only need 250 ml or 250 cm³ of water so I divided the weight by 4:
Na and Cl
23 and 35.5
58.5
58.5 / 4
14.625 grams of sodium chloride
Results
When I viewed the solution I found that the solution was saturated at the beginning of the preparation. So I added a little more water and stirred it for a longer time until the solution became transparent. There were no other problems that I could observe. Therefore it should be a one mole solution of sodium chloride
Evaluation
Difficulties
I had to make sure that I ripped the weight of the filter paper when weighing my sodium chloride. The beaker and stirring rod may have had sodium chloride left on them. So I rinsed them in to the flask using distilled water a few more times to make sure it was all gone. I found it hard to transfer the solution into the flask. So I used a funnel and made sure I rinsed that into the flask as well. When I had finished the preparation I took somebody else’s opinion on whether or not the solution was at the right level and it was just below to the line. So I added a lit distilled water until it was up to the right level and asked them again.
The reliability, accuracy and sensitivity of the techniques and equipment used
The scales where not very accurate and only measured to one decimal place so I may have had 14.64 grams of sodium chloride instead of 14.60 grams. The volumetric flask may have been slightly off 250 cm³ so the solution may have been too strong or too weak. The technique is also weak as there may be the smallest particles of sodium chloride left in the beaker or on the stirring rod so it would make it a weaker solution. There may also be sodium chloride left in the filter paper.
How it could be enhanced
The next time I could use more accurate scales so I used the right amount of sodium chloride. I would also wash and rinse the equipment more time to make sure it was cleaner and more of the sodium chloride was in the solution.
Vocational implications
Sodium chloride as a preservative
Sodium chloride is used to store foods in such as carrots and potatoes in a tin to keep them from going off. They have machines that add salt to the water so they don’t use the same technique. There is also hardly any safety procedures as they are not mad by man. The accuracy is less to use for a preservative as it is not essential that it is a one mole solution for an experiment. It is also made on a larger scale as more is needed and accuracy is not needed.
Lukas Chamberlain Page 02/05/2007