organic chemystery Flashcards
what is tautomerization?
POOP
interconversion of 2 isomers by simultaneous shift of proton and double bond. (moving electron cloud?)
what type of hybridisation is apparent in methane?
sp3 hybridisation (4 bonds surrounding it so s, sp,sp2,sp3)
which has the greatest polar bond?
C-F The bond gets increasingly polar as a more electronegative atom is attached to the carbon. Fluorine is the most electronegative element attached to the carbon here.
Secondary carbons are how many times more reactive than primary carbons?
Secondary carbons are x4 as reactive as primary carbons. Tertiary carbons are x5 as reactive as primary carbons. So radioactivity ratio is 1:4:5
tertiary radical more stable but more reactive
which of the following reactions requires a fine nickel catalyst? A elimination B halogenation C hydrohalogenation D hydration E hydrogenation
hydrogenation reactions (addition of H2 to an alkene = alkane) requires a stong calalyst like Nickel catalyst !
In what group is the Sn1 nucleophilic substitution reaction most likely to occur?
tertiary (and secondary) carbons. compounds that can form a stable carbocation react by the SN1 mechanism
what type of hybridisation is apparent in ethene?
sp2 (there are 4 bonds but one of them is a double bond so techincally 3 bonds so we do s,sp,sp2)
Which of the following compounds will cause a silver mirror to develop during the chemical test using Tollen's Reagent (Ag(NH3)2+)? A Aldehydes only B Ketones only C Aldehydes and ketones D Aldehydes and alpha hydroxy ketones E Carboxylic acids
Aldehydes and alpha hydroxy ketones. alpha hydroxy ketones have an -OH group on the carbon next to the carbonyl group which makes the compound more reducing and so able to reduce the reagent to liberate the silver atoms which form the mirror.
Reducing carbohydrates
which amino acid is not present as an enantiomer? A serine B alanine C glycine D cysteine E histidine
glycine: glycine cannot act as a stereoisomer as it has 2 identical atoms (2 H atoms) attached to the central carbon atom
in hyperconjugation reaction what type of hybridisation does the carbon centre change into?
sp3to sp2 . Radicals are stabilised by hyperconjugation.
Delocalisation of the bonding electrons from carbon next door by overlap with partly filled p orbital. Theres a net stabilising effect (less energy required to generate the radicals)
What is theMichaelis-Menten equation?
v = Vmax([S]/Km+[S])
C1-? alcohols are soluble in water before the long chain predominates and makes them insoluble?
C1-C3 alcohols are soluble in water.
As the chain length increases, solubility decreases, as the HYDROPHOBIC tail dominates and have higher boling points than alkanes
> > this is the same for COOH except its up to C4
what is the Baeyer test used to test for in organic chemistry?
test prescence of a double bond e.g alkene
a postive test is when the KMnO4 is used to oxidise the double bond and the purple colour disappears
What is the empirical formula for carbohydrates?
Cn(H2O)n
what is valence shell electron configuration of carbon?
1s2 2s2 2p2
What is the difference between homolytic and heterolytic bond cleavage?
Homolytic bond cleavage is when one electron is transferred resulting in the formation of radicals
Heterolytic bond cleavage is when 2 electrons are transferred resulting in formation of ions
is ethanal (acetal-aldehyde) chiral or achiral?
CH3-C=O
\
H
this is achiral as it onoly has 3 groups NOT 4!
if the highest priority (highest atomic number) groups are on the same side is it..
E- isomer
Z- isomer
Z - isomer
> on zee zame zide
The atom which has the higher atomic number is given the higher priority.
why is teritary carbocation more stable?
The tertiary carbocation is the most stable as it has 3 bonding pairs which each have electron clouds that can stabilise it.
When added together, an alcohol and carboxylic acid (ester) will not spontaneously react. What kind of catalyst is required for esterification?
A An inorganic acid catalyst, such as concentrated sulphuric acid.
B A strong basic catalyst, such as sodium hydroxide.
C A nickel catalyst.
D A nitrogen (II) oxide catalyst.
E A platinum catalyst.
OPTION
inorganic ACID is required to make the alcohol and the carboxylic acid react.
catalyst protonates the carbon allows resosnance, attack by alchol and removal of WATER (hydrolysis reaction)
How is ammonium sulphate used to separate proteins in purification?
A By using charged molecules to separate the mixture into fractions.
B By using the size of the molecules to separate the mixture into fractions.
C By acting as a binding partner to exploit the affinity of the target protein.
D By outcompeting the protein so that the protein precipitates out.
The ammonium sulphate is more soluble in water than the protein, so outcompetes the protein for water availability. Highly polar proteins require more salt to be added in order to precipitate out.
which acid is stornger?
propanoic acid or octanoic acid?
proponic acid stronger as it has the shorter carbon chain so more likley to give up the proton
as carbon chain gets longer, its more reactive and negative so tends to act more basic = weaker acid
Which of these contains a triple carbon bond? A Alkane B Alkene C Alkyne D Alkanols E No hydrocarbons contain triple bonds
OPTION C
A - alkanes contain single bonds B - alkenes contain double bonds C - alkynes contain triple bonds D - alkanols contain -OH group E - false
Why are ethers often used as solvents? They are very polar. They are very reactive. They are not very polar. They are not very reactive. They can form extensive hydrogen bonds between molecules.
OPTION D
Ethers also more polar than alkanes (due to Oxygen), but less polar than alcohols, and
Ethers can form hydrogen bonds with water they can’t form between other ether molecules.
Shorter they are = lower the boiling point
