Write beforehand. Aim- In this experiment we
Write up for Qualitative Analysis 1. Introduction- This experiment is for qualitative analysis so we are trying to find out what is in a substance. In this case we are using the flame test to try and discover what is in 4 unknown sample solutions that we have been given this is done by cross referencing the colour of the flame with 6 known solutions we test beforehand. Aim- In this experiment we are attempting to distinguish what substances are in the 4 unknown solutions by cross referencing with the 6 known solutions we test beforehand.Assumption- Not applicable for this experiment as we would have no clue as to what each unknown solution was. Risk Assessment- Material used/procedure- * The Flame Test * Gloves * safety glasses * lab coats * Bunsen burners * wire hoop * 4 unknown solutions and 6 known solutions * Hydrochloric acid Hazards- * Hydrochloric acid- Toxic, corrosive * Barium Chloride- Toxic * Calcium Chloride- Harmful * Copper Sulphate- Harmful * Lead Nitrate- Toxic, damaging to environment, oxidising * Potassium Nitrate- Oxidising Sodium Chloride- none unless there is contact with eyes * Bunsen burner- being burnt What could go wrong? – * Ingestion * Contacts with eye * Contact with bare skin * Burning of skin/clothing * Spilled solution/slippery floor Safety precautions- * Gloves to be worn * Lab coats to be worn * Safety glasses to be worn * Walk with equipment carefully * Keep chairs/stools under the table * Keep bags under the table out the way * No eating or drinking in the lab * When not using the Bunsen burner turn to safety flame In case of accident- Use eye wash station * Fire blanket * Wash hands/any part of skin with direct contact * Report accident * If burnt run under cold tap * Seek medical help Risk (high/medium/low explained) * Low – when all the above is taken into account and followed Method- 6 unknown solutions were set up in test tube racks, alongside them was Hydrochloric acid, a metal hoop was also needed to dip into the solutions.
Then lab coats, safety glasses and Gloves were equipped to ensure that safety hazards were avoided as much as possible.The Bunsen burners were then lit and put onto the safety flame. The equipment was then sterilised by dipping it into the Hydrochloric acid, and turning the Bunsen onto a roaring flame it was placed in the middle small triangle (the hottest part of the flame) and this step was repeated 5 times to get a reliable control flame colour. The hoop was dipped into one of the known solutions and placed in the hottest part of the flame. A short lived coloured flame was visible and this colour was recorded.After this the hoop was then sterilised in the hydrochloric acid again until the flame was the same colour as the control flame. This process was repeated until all 6 known solutions had been tested.
Then the 4 unknown sample solutions were then tested in the exact same way, and recorded. Comparisons were then made by cross referencing the colours from known and unknown solutions. Results- Name of solution/substance| Colour of flame| Barium Chloride | Yellow| Calcium chloride| Red| Copper Sulphate| Green|Lead Nitrate | Lilac| Potassium Nitrate| Purple| Sodium Chloride| Orange | Sample| Colour of flame| 1| Red| 2| Green| 3| Lilac| 4| Orange | Calculations- No calculations were used in this experiment to figure out the unknown solutions Conclusion- Seen we had unknown variables, we could not make a prediction to the colour that the flame would be. With the results that we gathered we can cross reference and deduct that Sample 1=Calcium Chloride, Sample 2=Copper Sulphate, Sample 3=Lead Nitrate, Sample 4=Sodium Chloride.
Evaluation- Overall we did the experiment as requested and as reliable as we could given the equipment that was on offer. A few thing may affect the results; the hoop was Sterilised by it being placed under the flame at the start, throughout the investigation we noticed that due to using only one hoop for the experiment, contamination had to be taken into account whether it be through not cleaning the hoop thoroughly, or mixing the solutions.The Hydrochloric acid, was also a problem due to using only one test tube full to clean the wire hoop, it would be carrying parts of all 10 known and unknown solutions in the end. These problems could be avoided by using a new sterilised wire hoop for each solution and also separate test tubes of Hydrochloric acid for each cleaning process.
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