14115195
Description
Flashcards by josephw weetch, updated more than 1 year ago
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Created by josephw weetch
over 7 years ago
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| Question | Answer |
| Purpose of recrystallisation | Purify impure solids |
| Step 1. | Cool and filter product under reduced pressure using Buchner apparatus as shown |
| Step 2. | Prepare solvent |
| If solvent is flammable | Heat over water bath |
| If solvent is water | Warm by placing the conical flask on a tripod and a gauze over a Bunsen |
| Step 3. | Dissolve impure solid in minimum hot solvent |
| Step 3. | Slowly add the solvent to the impure sample until it dissolves in the solvent. |
| How much solvent should you add? | The minimum volume required to dissolve the solid. |
| Step 4. | Once solid has dissolved, allow solution to COOL. Crystals of the desired product should form in the conical flask. |
| Step 5. | When no more crystals form, filter the crystals under reduced pressure and wash in COLD solvent |
| Step 6. | Dry under reduced pressure, and determine purity via mpt/TLC |
| Step 7. | C |
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