Foundations
Name this molecule: CH3CH2CH2CH2CH3
Pentane
Which peak do look at on mass spec to find the molecular mass of the compound
The peak on the far right
Name 4 factors affecting the rate of reaction
Nature of the reaction, temperature, light, state, concentration, catalysts
Name an example of a poor leaving group and an example of an excellent leaving group in nucleophilic substitution
Good: Cl-, Br-, I- (weak bases)
Poor: HO-, H-, NH2-, RO-
What reagent is required to form an alkane from an alkene
H2/Pd
How many lone pair of electrons does oxygen have
2
An absorption signal is split into how many lines on H NMR spectra
N + 1
If the rate of a reaction triples when the concentration of a reactant triples (and the concentration of the other reactants do not change) what is the order of that reactant
First order
Tertiary alkyl halides favor which mechanism of nucleophilic substitution and why
SN1 unimolecular mechanism because this mechanism goes through a carbocation and tertiary carbocations are the most stable
What reagent is required to form a ketone from an alkyne
aq. H2SO4/HgSO4
What is the difference between configurational isomers and conformational isomers
Interconversion of configurational isomers requires the breaking and reformation of bonds, while conformational isomers differ by rotation about a single bond
At what range do sp3 carbons show signals on C NMR
δ 0-90
If a reaction is in zero order, what are the units of k
mol/L/s
When an alkyl halide with R stereochemistry reacts via a SN2 pathway what is the stereochemistry of the resulting product
S - the reactant undergoes inversion of stereochemistry
What reagent is required to form an alcohol from an alkyl halide
-OH or H2O
Rank these groups from highest to lowest priority based on the CIP rules: -CH2OH, -COOH, -COCl
-COOH > -COCl > -CH2OH
Absorption is observed at a longer wavelength for non-conjugated systems and a shorter wavelength for conjugated systems - true or false?
False - in conjugated systems the energy change for electron excitement is smaller and absorption is observed at a longer wavelength than for non-conjugated systems
If a reaction is in second order what is the relationship between the concentration of the reactant and half life
The higher the concentration of the reactant the shorter the half life - half lives subsequently increase
As the substitution of a carbonyl compound increases, what happens to the rate of nucleophilic attack and why
It decreases due to electronic and steric effects
What reagent is required to form an alkene from an alkyne
1. Li/liq. NH3
2. H2O
Water, pentone, an acyl halide
What is a limitation of IR spectroscopy
1. Compounds containing the same functional groups will show very similar spectra - eg. ethanoic acid and butanoic acid
2. Spectra gives no indication of how many of a functional group are present
When measuring instantaneous rate, what point in time would you pick to measure the rate of reaction and why
You would choose a time as close to the beginning of the reaction as possible (the initial rate) as this is when we know exactly what concentrations of reactants are present
How do you form a Gringard reagent
React an alkyl/vinyl/aryl halide with Mg and ether
PCC