1636419
Description
Flashcards by megan.radcliffe16, updated more than 1 year ago
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Created by megan.radcliffe16
about 10 years ago
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| Question | Answer |
| what are the oxidising agents used with ketones and aldehydes? | H2SO4 and K2Cr2O7 |
| what is the observation when a reactant is reduced? | Turns from orange to green |
| what happens to primary alcohols during a) partial oxidation b) full oxidation | partial oxidation= aldehyde full oxidation= carboxylic acid |
| what conditions are needed to obtain aldehyde form primary alcohol? | warm and immediate distilling |
| what conditions are needed to obtain carboxylic acid? | Reflux and excess oxidising agent (acidified potassium dichromate) |
| what happens to secondary alcohols during oxidation? | become ketones |
| what conditions are needed during oxidation of secondary alcohols? | Heat |
| why can tertiary alcohols not be oxidised? | It is very difficult to oxidise as a C-C bond would need to be broken for the loss of a hydrogen bond to be broken |
| what simple tests can be used to distinguish between an aldehyde and a ketone? | Fehlighs solution tollens reagent |
| what does a positive fehlings solution test show? | Aldehyde present- shown by change in colour from blue solution to brick red precipitate |
| what does a positive Tollen's reagent test show? | aldehyde is present- forms a silver mirror (silver ions are reduced to silver metal) Ketones- no visible change |
| what is reduction? | the gain of hydrogen |
| what is the reducing agent for reduction? | NaBH4 |
| what are aldehydes reduced to? | primary alcohol |
| what are ketones reduced to? | secondary alcohol |
| what is the mechanism of reduction between propane and NaBH4? | Nucloephilic addition reaction |
| what is the mechanism of the reaction with HCN? | |
| what are the reagents used for the reaction with HCN? | H2SO4 and NaCN |
| what are the uses of esters? | Food flavourings solvents plasticisers |
| what to carboxylic acids react with to form an ester? | alcohols in the presence of a strong acid catalyst |
| what is the reaction between carboxylic acid and alcohol? |
Image:
esterification (image/png)
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| what are the characteristics of the esterification reaction? | the reaction is an equilibrium the reaction is slow (even though there is a catalyst) |
| what is ester hydrolysis? | the breaking down of an ester- producing a carboxylic acid and an alcohol |
| what is produced when ester hydrolysis is carried out in the presence of an alkali? What is the reaction called? | carboxylic salt reaction= saponification |
| what the reaction of saponification? |
Image:
SAPONIFICATION (image/png)
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| what is the other name for glycerol? | propane 1,2,3- triol |
| how is soap made? | fats/oils are hydrolysed by boiling with an alkali (NaOH) = a salt (soap) and glycerol |
| how is biodiesel made? | made by heating vegetable oils with methanol and sodium hydroxide |
| what happens during the reaction of biodiesel? | the vegetable oil is hydrolysed by the sodium hydroxide = fatty acid salt. |
| what is the fatty acid salt converted into with the reaction of biodiesel? | the salt is converted into the methyl ester by the reaction of methanol. |
| what are the advantages of using ethanoic anhydride when manufacturing aspirin? | less corrosive - does not produce HCl less susceptible to hydrolysis cheaper - not as many safety precautions |
| what are the problems with using carboxylic acids to make esters? | low yield- reversible slow- needs a catalyst |
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