Topic 6, PAST PAPER Q'S Flashcards
When alcohols react with concentrated phosphoric acid to form alkenes, what is this reaction called and why?
Elimination reaction
- As a molecule of water is eliminated from the alcohol to form the double bond in the alkene
What is meant by the term stereoisomers
Two isomers with the same structural formula but the atoms are arranged differently
What is the colour change for potassium dichromate when an alcohol has been oxidised
Turns from
Orange –> Green
Describe how to dry an organic layer to prepare it for distillation, including the name of a suitable drying agent
- Mix with, calcium Chloride, Magnesium sulfate, Sodium sulfate
- Filter the solution to separate from the drying agent
What may be a possible reason why there is no molecular ion peak in the mass spectrum of 2-methylpropan-2-ol
The molecular ion is unstable
Why would you cool the mixture in a reaction?
As the reaction may release a lot of heat
Why would you add anti-bumping granules to a mixture in a reaction?
To prevent violent boiling
Why would you heat under reflux in a reaction
To prevent the loss of any volatile substances, prevents vapour from escaping
How do granules prevent bumping
Prevention of uncontrolled boiling by distributing the heat more evenly
If compound X has OH functional group attached to its chain, why might it have a higher boiling temp than other hydrocarbons with a similar mass and shape
As the OH groups can form hydrogen bonds, this require more energy to break
Hydrocarbons only have london forces, whereas compound X has hydrogen bonds which are stronger
Why do isomers of hexane have lower boiling temperatures
-The isomers have branched chains
- they therefore do not pack as closely together
- their intermolecular forces are weaker so their boiling temperature is lower
Which bond is broken when chlorine molecules are converted into radicals in initiation
Sigma bonds
Give uses to waste plastic
- Cleaned and used again
- Recycled
- Incinerated to release energy
- As feedstock for cracking
What homologous group does it have to be to have cis-trans and E/Z isomers present
alkene
What does it mean to be a structural isomer
Having different connectivity between the atoms, atoms are bonded in a different order
How can you chemically test for an alcohol
Phosphorus chloride, you can observe the steamy fumes
What reaction is taking place from a halogenoalkene to an alcohol
Substitution/hydrolysis
