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| Pregunta | Respuesta |
| Organic reactions are slow and the substances are usually flammable and volatile. What is the problem with heating them with a Bunsen burner? | The substances will evaporate or catch fire before they have time to react |
| What is done to overcome the problems associated with organic substances being flammable and volatile? | Refluxing a reaction |
| Describe the process of reflux | The mixture is heated in a flask fitted with a vertical Liebig condenser. Anti-bumping granules are also added to make boiling smoother. |
| What is the purpose of distillation? | To separate liquids with different boiling points |
| Describe the method of distillation |
Distillation involves gently heating a mixture in a distillation apparatus. The substances will evaporate out of the mixture in order of increasing boiling point.
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| What can be used to purify a product that is insoluble in water? | Use a separating funnel to remove any impurities that do dissolve in water (e.g. salts or water-soluble organic compounds like alcohols) |
| How do separating funnels work? |
The organic layer is normally less dense than the aqueous layer, so should float on top. Most of the water-soluble impurities should have dissolved in the lower aqueous layer. A stopper can then be used to run off the aqueous layer and collect the product.
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| If you use separation to purify a product, the organic layer will end up containing trace amounts of water. What must be done to completely purify the product? | It must be dried - you add an anhydrous salt (e.g. MgSO₄ or CaCl₂). The salt is used as a drying agent. The mixture is then filtered to remove the agent |
| How do anhydrous salts act as drying agents? | It binds to any water present to become hydrated |
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