Chromotography – experiment writeup - Sample Essay
When I will do my experiment I will make sure that I wear my lab coat at all times when doing my experiment to protect my clothes from any spillages. I will also be wearing my goggles to protect my eyes from any of the substances which I will be using. I will also make sure to wear gloves when handling any chemical substances to protect my skin from any of the substances being used, and to prevent any contact being taken place with my skin and any of the chemicals. I will also be careful to prevent any glass breakage taking place.
Broken glass can cause open wounds to take place and even create a deep cut. But if any glass does break then I will make sure I keep the area where the breakage has taken place is clear and notify by subject teacher and try and clear up the area carefully. And when I use any electrical equipment I will make sure that my hands are dry and are not wet because electricity and water do not go on well together. I will be using the following chemicals: Copper Salts. This substance is very toxic if swallowed. (Copper Chlorides.
Any substance of this item over 1. 4 molar is very toxic and it should notified to users the effect of bad use of this substance. This substance is also harmful and if it touches your skin or eyes, it could irritate your skin and your eyes). (Copper Chromate. This substance can cause cancerous cells to form; the substance should not be isolated or even kept dry. Again this substance is also harmful is swallowed). (Copper Nitrate. This substance is very harmful if it is swallowed, if contact is made to the eyes and the skin then it can cause irritation. This substance is also highly flammable).
(Copper Sulphate.This substance is also harmful if swallowed, and can cause irritation to the skin and eyes. If an accident takes place involving this substance then it can cause long term side effects). Nitric Acid. This substance is very toxic if it is corrosive and can cause irritation to occur if any contact is made with this substance and the skin or eyes. This substance is also an oxidising agent so this substance can be flammable. If this is swallowed then you should make sure that the mouth is washed out with fresh tap water and tell the teacher about the incident and seek medical advice.
If any of the fumes given off is inhaled then you should make sure that a fresh supply of air is supplied to the person and the person takes medical advice from the GP. If the substance is splashed onto the eye then you should make sure that running water is flooded onto the eye and the person seeks medical attention. If the substance spills onto the floor then you should make sure the area is clear, a fresh supply of air is supplied to ventilate the air and the area is cleared up by using a mineral absorbent into a bucket.
The area should be cleaned up thoroughly to clear away any residue. Brass fillings. I will also make sure that none of the fillings get into my eyes as they could severely irritate my eyes by scratching the outer layer of my eye, to prevent this I will be wearing goggles. Plan/Method 1. Complete Risk assessment. 2. Place 30 cm3 of water into a 250 cm3 conical flask, while stirring add 15 cm3 of Nitric acid. 3. Weigh out accurately to two decimals places 1. 6 grams of Brass fillings. 4. Add the filling to the mixture in the fume cupboard. 5.
Allow the fillings to dissolve over 5 minutes while stirring constantly, during this procedure hazardous fumes can be given off so place the mixture in the fume cupboard to get rid of the poisonous nitrogen dioxide fumes. 6. Remove the solution from the conical flask and add it to another 250 cm3 conical volumetric flask. 7. Then go onto dilute Copper sulphate solution with water to make solution labeled A to F in a table. 8. Switch the colorimeter on and allow it to warm up. 9. Place 700nm filter in the colorimeter and put the meter to zero using a cuvette filled with water. 10.
Fill six other solutions labeled A to F and get the absorption values for each of them and record the values. 11. Fill another cuvette with the Brass solution and measure the absorption value and record it. 12. Plot a graph showing the values. 13. Use the graph to measure the concentration of copper ions in your brass solution. 14. Use the value to calculate the percentage of copper in your antique brass sample. Solution Copper Sulphate (aq)/ cm3 Water/ cm3 Concentration of solution g Cu/ cm3 Absorbance A 10 0 1. 60 0. 22 B 8 2 1. 28 0. 18 C 6 4 0. 96 0. 14 D 4 6 0. 65 0. 10 E 2 8 0. 31 0. 06 F 1 10 0. 16 0. 02 15.
Write a detailed report of your findings. Conclusions Absorbance of the unknown substance is 0. 14 which equates to 0. 95 Cm3. 0. 95/1. 6 x 100= 59% The percentage of copper in my brass is 59%. Evaluation Overall the experiment went well apart from some minor set backs. These were that when I had to add nitric acid the molar of the acid was 0. 5 but as I stirred the mixture no reaction of any kind was taking place so I had to add some more nitric acid, but as I added more nothing else seemed to happen to the fillings so my teacher had advised me to use a higher molar Nitric Acid which was very toxic.
When I put the acid into the conical flask I noticed some green gas coming out from the flask, which is why I placed the flask under an open window to let the gas out from the flask and into the fresh air outside. If I had taken this gas in then a serious incident would have taken place which is why I kept to my set procedure of how to go about and do the experiment, the safety of the experiment wasn’t so good after I had added the higher molar acid which is why I took extra precaution to do the experiment.
When I followed my set procedures I already had studied the possible hazards like the glass breakage, if the acid had came into touch with my skin and if I had taken in any of the fumes which were given out by the acids. These were all covered in my risk assessment which I already had thought out before I started the experiment which is why I was able to do the experiment without any serious hazards taking place and affecting me in any way.
As I had approached each step in my plan I kept referring back to my risk assessment so I had a good idea of what type of risks and hazards were involved. The method which I had used was pretty straight forward and I had practised the experiment using my method before the actual experiment after school in my own time, this helped me understand a bit more about the reason why I am doing this experiment and how I can make my results more efficient.
In my method I did not take into account the cuvette, this was a tiny glass piece of instrument which could affect my end results because of little fingerprints being on the out glass surface or small splashes of liquid. This would have affected my results and looking at my results I think I had made I mistake of making the outer surface of the cuvette covered with finger prints which I was able to see or small splash marks from other liquids.