2019 Year 12 IB Extended Essays

15. After a week check ring formation for clear definition record the number of rings formed. Use a 30cm ruler to measure ring distance from gel surface, ensuring to align ruler parallel to test tubes. S AFETY CONSIDERATIONS A risk assessment was conducted using student risk assessment for this experiment, see appendix 3.1. Cobalt (II) chloride is an irritant, health hazard, and environmental hazard and should be handled with great care using basic laboratory safety practices such as the use of gloves, lab coats and safety glasses. In addition to this, ammonia is a corrosive, acute toxin, and an environmental hazard. Supervision is required when handling this compound. To avoid the inhalation of the extremely pungent vapour, it is recommended the experiment be conducted within a fume cupboard or in a well-ventilated area. Care should be taken when using deionized water – should a spill occur, the substance can serve as a slip hazard to other laboratory partners. This is also a concern when using ammonia as it is also a liquid. M ETHOD E XTENSIONS An additional set of the above experiment was replicated, however, the cobalt (II) chloride was replaced with magnesium chloride. Although the chemical compounds were changed, the same method was applied (refer to appendix 2 for results). Unlike the first experiment, the rings were not as clear as the ring formations created through the cobalt (II) chloride reaction. Consequently, the magnesium chloride ring formations were neither used for data collection nor analysis. In addition to the conduction of a secondary experiment, a time-lapse recording was also taken in order to demonstrate the formation of precipitate rings within the cobalt (II) chloride and ammonia. The recording allowed for further inquiry within the investigation and provided extended qualitative analysis into the ring formation.

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