Flashcards in Organic Deck (33):
Identify the characteristic of the haloalkane molecule that enables it to undergo a nucleophillic substitution reaction: (Eg in bromo-propane) SPECIFIC
The Polar C-Br bond.
Give a condition needed to favour an elimination reaction in a halogenoalkane rather than a nucleophillic substitution reaction:
Give a use for sulfur dioxide that is formed as a byproduct in a reaction:
To make gypsum / plaster
OR to make H2SO4
Identify one feature of the infrared spectrum which supports the fact that this is an
alcohol. You may find it helpful to refer to Table 1 on the Data Sheet.
Explain how infrared spectroscopy can be used to identify this isomeric alcohol. (3 Marks)
-Peak at 3230-3550
-Run the infrared spectra (of the alcohols)
-Find the one that matches this spectrum
-Peak at 3230-3550
-Use fingerprint region
-And match with spectra in database
Butan-1-ol reacts with acidified potassium dichromate(VI) solution to produce two organic compounds.
Name the two compounds that form.
Butanoic acid CH3CH2CH2COOH
When chlorine gas dissolves in cold water a pale green solution is formed.
CL2(g) +H20(l) --> H+ + Cl- + HClO
Give the formula of the species responsible for the pale green colour in the solution of chlorine in water.
When chlorine reacts with water in BRIGHT sunlight, only two products are formed.
One is a colourless, odourless gas and the other is an acidic solution that reacts with silver nitrate solution to give a white precipitate.
Name the two products.
Colourless, odourless gas- O2
Acidic solution that reacts with silver nitrate - HCl
Cl2 + 2H20 --> HCl + O2
Write a equation for the reaction between sodium hydroxide and ethanoic acid.
CH3COOH + NaOH --> CH3COONa + H2O
Suggest why the concentration of sodium hydroxide in a solution slowly
decreases when left open to air
NaOH reacts with carbon dioxide (in the air)
Reasoning for choosing a rate determining step
-Step which includes the SPECIES in the rate equation
Two ketone isomers.
Some students were asked to suggest methods to distinguish between isomers Q and R.
One student suggested testing the optical activity of the products formed when Q and
R were reacted separately with HCN.
Explain why this wouldn't work.
-Product Q is a racemic mixture
-Racemic mixture is optically inactive
-Product from R is inactive as no chiral centre
IUPAC name for glycerol
Give a use for the mixture of sodium salts that form in a reaction with glycerol
Give a use for a mixture of methyl esters that form in a reaction with glycerol
Name a suitable reagent for the reduction dinitrobenzene, to a phenyldiamine (benzene with two NH2 groups)
write an equation for this reaction using [H] as the reducing agent
C6H4(NO2)2 + 12[H] --> C6H4(NH2)2 +4H20
Repeating unit of kevlar
Kevlar used as inner lining of bicycle tires.
Outer tyre made of polymerised alkenes
State the difference in biodegradability of the two.
Use your knowledge of the bonding in these polymer molecules to explain this
-Kevlar is biodegradable but polyalkenes not
-Kevlar has polar bonds/has peptide link/ is a poly amide
-Can be hydrolysed/attacked by nucleophiles/acids/bases/enzymes
-Polyalkenes not polar/non- polar bonds
Outline a three step synthesis of CH3CH2NH2 starting from methane. Your first step should involve the formation of CH3Cl.
In your answer, identify product of 2nd step and give reagents and conditions for each step
EQUATIONS & MECHANISMS NOT REQUIRED (6 MARKS)
Start with CH3CN
Step 1: React with Cl2 under UV light
Step 2: React with aqueous and alcoholic KCN (Allow UV)
Step 3: React with H2/Ni
Role of hydroxide ion in mechanism:
Role is lone pair donor/base
Fermentation reaction with 2 essential conditions:
C6H12O6-----> C2H5OH + 2CO2
-No oxygen (anaerobic)
-(Enzymes from) yeast
State the meaning of the term carbon-neutral
-No net/overall Carbon Dioxide emission to the atmosphere
Mean bond enthalpy: (2 marks)
-Enthalpy (energy required) needed in breaking a covalent bond
-Averaged over a range of compounds
(conditions: constant pressure)
Steps for identifying a molecule NMR large 8 mark question;
-State absorbtion peak (eg O-H 3230-3550)
-state peak numbers and infer (4 h1 peaks therefore 4 different hydrogen environments)
-Simplify integration splitting
Give two reasons why Tetramethylsilane is a suitable standard
-All protons in same environment
Give an example of a solvent which is suitable for use in recording an nmr spectrum, Give a REASON
-"Proton Free" (means no hydrogen atoms)
What can the reaction of alcohols (eg butan-2-ol) with concentrated sulfuric acid give you?
and name the role of h2so4 in producing byproduct.
Can produce multiple alkenes, and a ketone as a byproduct. (Of the same alkyl eg butan-2-ol would produce multiple different butenes and butanone)
ROLE OF SULFURIC ACID IN KETONE PRODUCTION: OXIDISING AGENT
Role of sulfuric acid when it reacts with solid sodium chloride
Conditions for catalytic cracking:
Icicle looking transmittance on nmr spectrum over O-H absorbtion area, is it a peak?
No, noticable peaks are large and wave looking
Is a singlular sharp peak above C=O a peak?
Yes. (If that is the only peak most likely an aldehyde)
Reaction where C3H6 is produced from CH3CH2CH2Br. Identify reagent and conditions:
NaOH and ethanol
Reasons for a molecule not showing stereoisomerism
-Not having a chiral centre