Chapters 14 & 15 Flashcards
What are the 4 layers of the atmosphere
Troposphere
Stratosphere
Thermosphere
Mesosphere
Where is the stratosphere
The outer part above 10-40km above the Earth’s surface.
How does the ozone layer protect us?
It absorbs UV Radiation.
Living organisms would get sun burns and even skin cancer.
Why are organohalogens so useful
Because they are volatile and inert and safe.
Why are organohalogens so inert?
Because the C-F and the C-Cl bonds are very strong and they require a lot of energy to break.
What are nucleophiles?
They are particles that are attracted to partially positive atoms and they donate a pair of electrons, to form a new sigma covalent bond.
What are the main nucleophiles
OH-
OH2
NH3
Where do nucleophiles always attack from
The back of the C- X bond.
Why do nucleophiles always attack from where they do?
There is less repulsion between the lone pair of electrons on the nucleophile and the high electron density around the highly electronegative atom.
What is hydrolysis
Breaking of bonds using OH2 or OH
How are haloalkanes converted to alcohol
Nucleophilic substitution.
What are the varying strengths of Nucleophiles
Strongest to weakest:
NH3 > OH- > H2O > Any halide.
Why is NH3 stronger than H2O
Strong nucleophiles consist of central atoms with a lower EN. This makes it more likely to donate a pair of electrons to.
Why is OH- stronger than H20
OH- can induce a heterolytic fission between C and a halide faster than H20 can due to a higher repulsion.
How do the rates of hydrolysis change as you go down group 7?
Bond enthalpy of the C-X bond decreases.
So, the weaker the bond enthalpy,
Less energy required to break the C-X bond.
Less time taken to complete the reaction.
So it gets faster as you go down the group.
How can you prove the rates of hydrolysis down group 7?
Add AgNO3 to the haloalkane, to produce an alcohol and a coloured silver halide precipitate.
In these reactions, the nucleophile is water and the halide leaves to bond with the silver ions.
AgCl
White
AgBr
Cream
AgI
Yellow
Why is an organohalogen more likely to produce CL radicals rather than F radicals?
Because the bond enthalpy of CF is much higher and stronger.
Hence, it requires more energy to be broken, so instead a Cl radical is created.
Where can you get NO2 from
Planes and lightning.
How can you go from an alcohol to a carboxylic acid
React it with an excess of oxidising agent
With h2so4/k2cr2o7
REFLUX
ONLY FOR PRIMARY ALCOHOLS
How can you go from an alcohol to an aldehyde
React it with oxidising agent
With h2so4/k2cr2o7
DISTIL
ONLY FOR PRIMARY ALCOHOLS
How can you go from an alcohol to a ketone
React it with oxidising agent
With h2so4/k2cr2o7
REFLUX
ONLY FOR SECONDARY ALCOHOLS
What types of alcohols can become ketone
Secondary alcohols
What types of alcohols can become carboxylic acids?
Primary alcohols
What types of alcohols can become aldehydes?
Primary alcohols
Why can’t ketones be further oxidised?
The carbon in the ketone group has only 2 valence electrons, which is not enough for a carboxylic group.
How can you convert an alcohol into an alkene
Add concentrated h3po4.
REFLUX
What type of reaction is converting an alcohol into an alkene
Elimination
or dehydration.
How can you convert an alcohol into a haloalkane?
Add concentrated h2so4 and NaX (X- the halide)
REFLUX
They will react to form HX. This will react with the alcohol and turn it into a haloalkane.
When converting an alcohol into a haloalkane, why can’t you use HX directly?
It’s quite toxic and they can produce a variety of other harmful products.
