14067561
Description
Flashcards by josephw weetch, updated more than 1 year ago
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Created by josephw weetch
almost 6 years ago
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| Question | Answer |
| Suitable for: | Separation of pure liquid from impurities |
| Apparatus used (9) | pear-shaped flask condensor Rubber tubing Stand and clamp Screw-cap adaptor Receiver adaptor Still head Thermometer Heat source |
| Where does water enter? Show diagrammatically | Waterin at lower end of receiver |
| Step 1. | Flask is clamped by its neck and still-head adaptor is connected to flask. One ground-glass joint of the still-head is fitted to the screw-cap adaptor and the other to the condenser. The joints are greased. |
| Step 2. | A second clamp is placed around the receiver adaptor at the point at which it is attached to the condenser. This removes the need to clamp the condenser as it will be sufficiently supported at both ends. |
| Step 3. | Rubber tubing is used to connect inlet of condenser to tap and outlet to sink. Water enters condenser at the lowest point. |
| Step 4. | A conical flask is used to collect the distillate so that the distillation apparatus isn't completely airtight |
| Step 5. | Once the apparatus is set up, the flask is heated and the mixture in the flask will start to boil. The different liquids in the mixture will condense out with lowest boiling point first. |
| Step 6. | Vapour mvoes out of the flask up into other parts of apparatus, leaving behind the less volatile components in the mixture. |
| Step 7. | Once the vapour reaches the cold condenser, it condenses and becomes a liquid which drips into the collecting flask |
| How to remove acid impurities? | Add sodium carbonate and shake the mixture in the separating funnel. |
| Why do you need to slowly open the tap? | Let out CO2 gas formed by reaction of acid with Na2CO3, preventing gas pressure build up. |
| Final step: | Na2CO3 aq. layer removed, organic layer washed with water before running both layers off into two separate flasks. |
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