organic paper 1 Flashcards
explain why there is an attraction between c=c double bond and br2
M1 C=C electron rich / area of high electron density
M2 Br-Br becomes polarised
M3 δ+ Br attracted to C=C
problem of distillation
Anti-bumping granules
1a no anti-bumping granules / add anti-bumping
granules
1b to create smaller bubbles / to prevent large
bubbles / to prevent mixture jumping into
condenser
Stage 2
Open system with no thermometer
2a system should be closed (above flask) to
prevent gases escaping
2b should be closed with (bung +) thermometer
2c to allow collection of propanone (only) / to
prevent distillation of other components / to
stay in suitable temperature range
Stage 3
The water direction in the condenser
3a water flows in wrong direction through
condenser / change water direction
3b condenser not cool enough / not full of water
3c product may not condense / comes through as
gas
explain why propanone has a lower bp than propan2ol
M1 propan-2-ol has stronger intermolecular forces
M2 propan-2-ol has hydrogen bonds between molecules
M3 propanone has dipole-dipole forces and/or van der
Waals’ forces
state the benefit to life on earth of ozone in the upper atmosphere
Absorbs (harmful) ultraviolet / uv (light / radiation)
suggest one reason why use of fcfs were not restricted for several years
- lack of evidence that ozone was being depleted
- lack of alternatives to CFCs
- commercial interest to continue to use CFCs
- hard to obtain international agreement
state and explain how cdc-11 is able to contribute to global warming
M1 absorbs infrared radiation
M2 molecule has polar bonds
naphtha to propene
M3 (thermal) cracking
M4 to make alkenes / propene / shorter molecules
crude oil to naphtha
M1 fractional distillation
M2 separated into mixtures of compounds with similar boiling
points / similar sized molecules
propene to polypropylene
M5 (addition) polymerisation
M6 molecules joined together or to produce long chain molecule
why poly(propene) is unreactive
no polar bonds (in chain) / non-polar
suggest why it’d benenfiial for some polymers to be biodegradable
to prevent build-up of waste (in landfill) OR
they can be broken down by natural processes
define the term enthalpy change
Heat (energy) change at constant pressure
explain why the value given for the o=o bond enthalpy is not a mean value
Oxygen / O2 is the only substance that has O=O bond
A student has samples of these four compounds but does not know which is which:
* butanoic acid
* 2-methylpropanal
* 2-methylpropanoic acid
* 2-methylpropan-1-ol
Step 1: Two of these compounds can be identified by simple chemical tests.
Step 2: The other two compounds, that contain the same functional group as each
other, can then be distinguished using a spectroscopic technique.
Describe how these two steps could be used to identify which compound is which.
Stage 1
Identifying aldehyde / 2-methylpropanal
1a Tollens’ or Fehling’s
1b silver mirror or orange-red precipitate
Stage 2
Identifying alcohol / 2-methylpropan-1-ol
2a acidified potassium dichromate
2b (orange to) green
2c tests done in suitable sequence to distinguish
aldehyde from alcohol,
Stage 3
Distinguishing the acids
3a using IR spectroscopy to distinguish the two
acids (or other suitable technique)
3b use finger-print region of IR spectrum (feature
of spectrum to use)
3c look for exact match to spectra of known
compounds (what the difference is)
Analysis of the products of this reaction shows the formation of a compound with the
empirical formula CCl2F
Give an equation to represent a termination step forming this compound.
Show the structural formula of the product in the equation.
*CCl2F → CCl2FCCl2F