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| Questão | Responda |
| List 3 artificial sweeteners | Saccharin Cyclamate Aspartame |
| Burns with a smoky yellow flame | Benzene |
| Decolourises bromine water | Alkene |
| Produces carbon dioxide when reacted with a metal carbonate | Carb A |
| White fumes when reacted with \(PCl_5\) | OH group |
| Yellow-orange ppt when reacted w/ 2,4-DNPH | Carbonyl group (not a Carb A) |
| Red-brown ppt with Fehling's or Benedicts | Aldehyde |
| Silver mirror w/ \(AgNO_3\) + \(NH_{3(aq)}\) | Aldehyde |
| Antiseptic pale yellow crystals w/ \(I_2\) /NaOH | \(CH_3\)-C=O Or something which oxidises to it |
| Is phenol solution neutral, alkaline or acidic? Why? | Acidic b/c O's LP is pushed into benzene's delocalised ring structure making the OH bond more polar so it loses \(H^+\) |
| Can phenol be oxidised? | No, it is not readily oxidised |
| 2 reactions which increase chain length | Reflux w/ HCN/KCN Friedel-Craft's alkylation |
| Names of the 2 reactions which decrease chain length | Hofmann's degradation Hunsdiecker reaction |
| Define: hazard | Potential to do harm |
| Define: risk | Likelihood of harm |
| List 4 precautionary measures that can be taken to reduce risk | Use a fume cupboard Reduce scale Look for an alternative safer route Replace a reactant w/ a less toxic alternative |
| 2 ways of separating isomers | Thin-layer chromatography Electrophoresis |
| 2 ways to make single isomers | Asymmetric synthesis Use of chiral auxiliaries |
| Describe combinational chemistry | AN automated process by which many compounds all similar to a 'lead' compound are produced very quickly to see if they have lower side effects or more medical benefits as drugs than current treatments. They are all tested and then possibles kept in a large digital library. |
| What is a solid phase reaction? | Compounds are bonded to polystyrene-based polymer beads and the reaction takes place on them. The product remains bonded to the beads and excess reactants can be washed away. |
| Why are sold phase reactions using polymer beads useful? | Because 1 end of the reactant mol is fixed so all reactions have to happen at one end. |
| What do you heat with during reflux? | An electric heater |
| What can be added to remove acid? | \(NaHCO_3\) |
| What is solvent extraction? | When you add a solvent to a product in another solvent and the product is more soluble in the new solvent. When shaken it dissolves in the added solvent leaving impurities in the original layer, and a separating funnel can be used to tap off the lower layer, separating the product from another impurity or unwanted product which is more soluble in the other solvent. |
| Describe re-crystalisation | Add hot solvent till solid just dissolves Let solution cool slowly Crystals will form but impurities won't fall out of solution because they aren't near saturation. Remove the crystals by filtration and wash them with minimal ice cold solvent Leave to dry. |
| What can you add to remove water from a mixture? | \(CaCl_2\) granules |
| What are inside fractional distillation columns? | Glass beads |
| How do you determine melting point? | Put solid in capillary tube Place in oil w/ thermometer Slowly heat and stir Read the temperature when the solid just melts. |
| How do you make cholesteryl benzoate | Dissolve cholesterol in pyridine Add benzoyl chloride Heat in a steam bath for 10 mins Cool and add methanol Filter off crystals of ester and wash with methanol Recrystallise using ethyl ethanoate as a solvent. |
| How do you make methyl-3-nitrobenzoate? | Dissolve methyl benzoate in cold conc sulphuric Add 50/50 mix of conc nitric and sulphuric dropwise constantly stirring. Stir for 15 mins Pour over crushed ice When melted filter off crystals wash with water re-crystallise w/ ethanol |
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