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laboratory_exercises:determination_of_low_solubilities
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laboratory_exercises:determination_of_low_solubilities [2023-07-24 15:02] Gennaro Nesso |
laboratory_exercises:determination_of_low_solubilities [2023-09-16 15:43] (current) Susanna Salmien-Paatero |
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| ==== Learning Goals ==== | ==== Learning Goals ==== | ||
| - | Here the learning goals and purpose | + | In this exercise, |
| \\ | \\ | ||
| Line 22: | Line 22: | ||
| Therefore, an A* activity is produced by:\\ | Therefore, an A* activity is produced by:\\ | ||
| - | {{: | + | {{: |
| + | |||
| + | and the solubility is:\\ | ||
| + | {{: | ||
| + | |||
| + | Certain errors may arise in this type of determination.\\ | ||
| + | For example, it may be necessary to correct for the self-absorption of the active solid, or to arrange the experimental procedure so that this may be avoided.\\ | ||
| + | Care must also be taken to avoid errors due to absorption on apparatus. | ||
| + | |||
| + | In this experiment the solubility of strontium sulphate is determined and at the same time errors likely to arise are investigated.\\ | ||
| + | < | ||
| + | |||
| + | \\ | ||
| + | |||
| + | === Experimental Procedure === | ||
| + | -Take two 2 cm< | ||
| + | -Centrifuge at 5000 rpm for 5 min and then pour off supernatant into the waste beaker provided. | ||
| + | -Wash repeatedly with distilled water using at least 100 cm< | ||
| + | -Add 10 cm< | ||
| + | -Meanwhile dilute the strontium nitrate solution by a factor of 100 in the volumetric flask with distilled water– use 0.25 cm< | ||
| + | -Add 10 cm< | ||
| + | -Add 1 cm< | ||
| + | -Add 1 mL of the 100x diluted solution to a 2< | ||
| + | -Once the strontium sulphate has equilibrated, | ||
| + | -Add 1 cm< | ||
| + | -The 5< | ||
| + | -Count all 5 vials on liquid scintillation counter using < | ||
| + | |||
| + | \\ | ||
| + | |||
| + | As the majority of the activity is in the precipitate, | ||
| + | |||
| + | From the results obtained the solubility of strontium sulphate may be determined as follows:\\ | ||
| + | |||
| + | *Let count of 1 cm< | ||
| + | *Let count of 1 cm< | ||
| + | *Thus, 100 z cpm is equivalent to 0.1 g Sr(NO< | ||
| + | *y cpm is equivalent to: | ||
| + | *Solution of SrSO< | ||
| + | |||
| + | \\ | ||
| + | |||
| + | ==== Questions for the Students ==== | ||
| + | -What are the sources of error? | ||
| + | -Highlight the potential problems of using < | ||
| + | |||
| + | \\ | ||
| + | |||
| + | ====Safety Aspects=== | ||
| + | *A lab coat, gloves and safety spectacles must be worn.\\ < | ||
| + | *DO NOT dispose of any liquid or solid waste down sinks or in waste bins.\\ Place in the waste buckets provided. | ||
| + | |||
| + | \\ | ||
| + | |||
| + | ====Work report==== | ||
| + | The work report about this exercise should contain clear description of the performed work presenting the original theory, used equipment with settings, radionuclides with their activities and reference dates, answers to the two questions above, and finally the calculated results. | ||
| + | |||
| + | \\ | ||
| + | ====Preparation for the Lab Supervisor==== | ||
| + | |||
| + | ===Equipment=== | ||
| + | *Centrifuge\\ | ||
| + | *Liquid scintillation counter\\ | ||
| + | *1 mL autopipette\\ | ||
| + | |||
| + | \\ | ||
| + | |||
| + | === Consumables === | ||
| + | *4-5 mL of 2 M sulphuric acid | ||
| + | *15 mL centrifuge tubes x 2 | ||
| + | *> 100 mL of H< | ||
| + | *Scintillation vials x 5 | ||
| + | *50 mL of scintillation cocktail | ||
| + | *1 mL tips | ||
| + | *Waste beaker\\ | ||
| + | *Glass beaker x 2 for H< | ||
| + | * Polystyrene or other type of base to stand centrifuge tubes in 25 mL volumetric flask\\ | ||
| + | |||
| + | \\ | ||
| + | |||
| + | === Source === | ||
| + | 4 mL of < | ||
| + | |||
| + | |||
| + | |||
| + | |||
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| + | |||
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laboratory_exercises/determination_of_low_solubilities.1690203770.txt.gz · Last modified: 2023-08-28 22:10 (external edit)