Module 4 Flashcards
(16 cards)
Nucleophile
An atom or group of atoms that is attracted to an electron-deficient carbon atom, where it donates a pair of electrons to form a new covalent bond.
Electrophile
An atom or group of atoms that is attracted to an electron-rich centre, where it accepts a pair of electrons.
Structural and Stereoisomers
Structural isomers are compounds with the same molecular formula, but different structural formulae.
Stereoisomers are compounds with the same structural formula, but with a different arrangement of the atoms in space.
State two features of molecules that enable them to show E/Z isomerism.
- A carbon-carbon double bond
- Different groups attached to each carbon atom of the double bond
Homologous Series
A series of organic compounds with the same functional group but with each successive member differing by CH₂.
What is the colour change of sodium dichromate(VI)?
Orange to green
What is a sigma-bond?
A bond formed by the overlap of one orbital from each bonding atom, consisting of two electrons and with the electron density centred around a line directly between the nuclei of the two atoms.
What is a pi-bond?
A bond formed by the sideways overlap of two p-orbitals, containing two electrons and with the electron density concentrated above and below the line joining the nuclei of the bonding atoms.
Define homologous series
A series of organic compounds with the same functional group but with each successive member differing by CH₂.
Describe homolytic fission
Each bonding atom receives one electron from the bonded pair
forming two radicals
Describe how a σ-bond forms
Overlap of orbitals directly between the bonding atoms
Describe how the student can recrystallise the impure crystals to obtain x
Dissolve in the minimum quantity of hot water/solvent
Cool AND Filter AND leave to dry
Ethanol is oxidised to ethanoic acid using acidified potassium dichromate(IV) solution. What is the reason for heating under reflux?
To prevent any substances escaping.
Apart from recycling, state two methods for usefully processing waste polymers.
Combustion for energy production.
Use as an organic feedstock for the production of plastics and other organic chemicals.
How do you know which layer is the organic layer?
Add some water to the mixture, the layer that gets bigger is the aqueous layer.
Describe a method to obtain a pure sample of x (e.g. cyclohexanone) from the distillate.
Shake and leave to settle in a separating funnel.
Separate layers by tapping off.
Add a small amount of anhydrous magnesium sulfate/anhydrous calcium chloride to organic layer in a dry conical flask.
Redistil the organic layer.
Collect fraction distilling at x temperature.
