Organic Chemistry Flashcards
Give the reaction conditions and mechanism for the reaction of 1-bromopropane with KCN.
Name this reaction.
CONDITIONS
- aqueous ethanolic conditions (to ensure both substances dissolve)
- heated under reflux
Give the reaction conditions and mechanism for the reaction of NH3 with 1-bromopropane to form 1-aminopropane.
Name this reaction.
- concentrated solution of ammonia in excess
- heated in a sealed container
Give the reaction conditions and mechanism for the reaction of NaOH with 1-bromopropane.
Name this reaction.
- warm, not hot
- aqueous, not ethanolic
- low concentration NaOH
- refluxed
Percentage yield is a measure chemists use to quantify the effectiveness of a reaction.
Give two ways a reaction may have a lower percentage yield than expected.
Why is percentage yield important?
LOSS of product:
- loss during transfer/separation/purification
- side-reactions
- limiting reactant/incomplete reaction
IMPORTANCE:
- efficient conversion of reactants to products
Define hydrolysis.
The splitting of a bond using water
Define mean bond enthalpy.
The energy required to break one mole of a covalent bond, averaged out over many different compounds
Why is atom economy important?
IMPORTANCE:
- high a.e minimises waste and maximises the mass of reactant that ends up in the product
- high a.e means less mass of reactant needed, so reduction in transport costs and waste disposal
2-chlorobutane can react with NaOH to form 2 position isomers.
Given that the two isomers are alkenes,
Name and give the reaction conditions for this reaction.
Outline the mechanism.
- base elimination
- hot, ethanolic, concentrated NaOH
- heated under reflux
mechanism given
In organic synthesis, fractional distillation is a method of separating two substances with different boiling points.
[6 marks] Describe, in full detail,
Give the test-tube test for alkenes.
-add bromine water
- bromine water is decolourised
Give the test-tube test for carboxylic acids.
- Add sodium hydrogen carbonate
- fizzing, production of CO2
- Identification of CO2 can be done via bubbling through limewater which goes cloudy
Give the test-tube test for alcohols. Explain the purpose of your reagent in this test.
- Add K2Cr2O7/H+, acidified potassium dichromate, which is orange like bromine water
- positive test, (which can only occur for primary, or secondary alcohols) is:
- orange to green
The purpose of the K2Cr2O7 is an oxidising agent.
Give the test-tube test for aldehydes and ketones.
Fehling’s solution:
- add to substance and heat in a water bath
- positive test(presence of an aldehyde):
- blue solution to red precipitate
Tollens reagent:
- add to substance and heat in a water bath
- silver mirror forms on the surface of the test tube
Give the test-tube test for halide ions.
- add dilute nitric acid HNO3, then add AgNO3 silver nitrate.
- F none
- Cl white precipitate
- Br cream precipitate
- I yellow precipitate
Give the test for hydroxide ions in solution.
Add MgCl2
Mg2+ + 2OH- -> Mg(OH)2(s)
In the production of PVC (poly(chloroethene)), a plasticiser is often added.
Explain why a plasticiser is added to PVC.
- to make the polymer more flexible
- by pushing the polymer chains further apart
- weakening the VdW forces between polymer chains
