4.2.2 Haloalkanes Flashcards
(21 cards)
What happens to the polarity when you go from C-F to C-I?
- Polarity decreases.
What is the electron deficient carbon susceptible to?
- Attack by nucleophiles.
Define nucleophile.
- Electron pair donor.
What reaction and chemical is needed to go from a haloalkane to an alcohol?
- Hydrolysis and NaOH.
How do you measure the rate of a halogenoalkanes being hydrolysed?
- The halogenoalkane is heated with silver nitrate. Ethanol is also added to act as a solvent. Water acts as a nucleophile.
What is the formula for calculating the rate?
- 1/time taken for precipitate to form.
What observation can be made for a chloroalkane?
- White ppt.
What observation can be made for a bromoalkane?
- Cream ppt.
What observation can be made for an iodoalkane?
- Yellow ppt.
How do you make measuring the rate at which halogenoalkanes are hydrolysed a valid investigation?
- Use equal moles of haloalkane.
- Use haloalkanes with the same chain length.
- Use a water bath to ensure constant temperature.
Out of all the halogenoalkanes, which one reacts the fastest?
- Iodoalkanes.
Why do fluoroalkanes not react readily?
- Because they have such a strong bond that they do not react readily.
What happens to the bond strength of haloalkanes as the size of the atom increases?
- The bond strength decreases.
What does the ozone protect humans against?
- The sun’s UV rays.
What does UV rays damage in the human body?
- Damages DNA causing skin cancers.
What are the uses of CFCs?
- Coolants in fridges
- Propellants in aerosols
- Degreasing circuit boards
- Dry cleaning solvents.
What occurs when UV radiation strikes a CFC molecule?
- It is broken down by homolytic fission to produce a chlorine radical.
What happens when a chlorine radical collides with ozone?
- It steals an oxygen atom to form a chlorine monoxide radical and leaves behind an oxygen molecule.
What happens when the chlorine monoxide radical collides with a free oxygen atom?
- The two oxygen atoms bond to form an oxygen molecule, leaving behind the chlorine radical which is free to attack more ozone.
What are the steps required to purify an organic liquid?
- Use a separating funnel to separate organic and aqueous layers.
- The organic layer sits on top of the aqueous layer.
- Dry the organic layer with an anhydrous salt.
- Re-distil to purify the product at 83 degrees celsius.
Why does the organic layer sit on top of the aqueous layer?
- The organic layer is less dense.
