organic cramming y12 AHHHH

yes we have another test....

structural isomer definition

molecules with the same molecular formula, but different structural formula.

positional isomer definition

same molecular formula, with the same functional group attached at different positions along the carbon chain.

functional group isomer definition

same molecular formula, with the same atoms arranged to give different functional groups.

chain isomer definition

same molecular formula, but with a different arrangement of the carbon chain

stereoisomer definition

same molecular formula, same structural formula, with a different arrangement of the atoms in space

how do the cahn ingold prelog rules for assigning priority functional groups in E-Z isomers work?

compare the 2 functional groups above and below on both carbons. the element with the highest atomic number takes the priority- if a tie, move 1 bond further along the chain, and repeat until priority group assigned.

how to tell between E-Z isomers (just Z listed on def)

Z= zusammen (together), so functional groups will be on the same side.

fractional distillation def

separating a mixture of liquids by heating to vaporise them, then condensing them into fractions based on boiling point.

how do the vapours pass up the fractionating column? (fractional distillation)

via a series of trays containing bubble caps until they arrive at a tray that is sufficiently cool

thermal cracking conditions

high temperature, high pressure

thermal cracking products

often produces a higher proportion of straight chain alkenes and/or hydrogen

catalytic cracking conditions

zeolite catalyst containing aluminosilicates in a honeycomb structure. high temperature, slight pressure

catalytic cracking products

often produces branched alkanes, cycloalkanes and aromatic compounds.

sulfur dioxide formation & consequence

sulfur containing impurities in crude oil react with oxygen.
acid rain.

oxides of nitrogen formation & consequence

formed in petrol engine where temp is high enough for nitrogen and oxygen from the air to combine.
acid rain and photochemical smog.

carbon monoxide formation and consequences

from incomplete combustion.
toxic (binds to haemoglobin)

particulates formation and consequences

incomplete combustion
exacerbate asthma, global dimming and cause cancer.

unburnt hydrocarbons consequence

photochemical smog

flue gas desulfurisation slurry of CaO (lime) and water sprayed into flue gas equation WITH STATE SYMBOLS.

CaO (s) + SO2 (g) + 2H2O (l) + 1/2O2 (g) —> CaSO4·2H2O (s)

CaSO4·2H2O name

gypsum

flue gas desulfurisation limestone WITH STATE SYMBOLS

CaCO3 (s) +1/2O2 (g) + SO2 (g) —> CaSO4 (s) + CO2 (g)

how do catalytic converters work

ceramic honeycomb (maximises surface area to reduce amount of expensive metal needed) coated with platinum and rhodium metals (catalysts).

key reactions catalytic converter (CO + NO and hydrocarbon)

2CO (g) + 2NO (g) —> N2 (g) + 2CO2 (g)
hydrocarbon + NO —> N2 + CO2 + H2O

how does the greenhouse effect work?

Visible light passes through the atmosphere, which is then absorbed and re-radiated as infrared radiation. Covalent bonds in greenhouse gases absorb this IR radiation, causing the bonds to vibrate more, trapping heat energy in the atmosphere.

how does the Cl-Cl bond break in a free-radical substitution reaction?

homolytically (with 1 electron to each chlorine)

why are chain reactions not very useful?

because they produce a mixture of products

what happens to the boiling point of a halogenalkane if you increase branching and why?

decreases, as molecules can’t pack as closely together

how does the boiling point of a halogenoalkane compare with an alkane with a similar chain length?

greater, as Mr is greater (stronger vdw forces) and polar C-X bond (permanent dipole dipole forces)

are halogenoalkanes soluble in water?

No- they can’t form hydrogen bonds with water (only dipole-dipole/vdw forces, which aren't strong enough to overcome water's hydrogen bonds.

Are halogenoalkanes soluble in organic solvent?

Yes- they form van der Waals (and dipole-dipole) forces with the organic solvent molecules

what is a nucleophile?

an electron pair donor

how does the OH- ion act in elimination?

A base (removes H+ ion from halogenoalkane)

how do van der waals forces arise?

Continuous movement of the electron clouds creates a temporary dipole in one molecule, which induces a dipole in a neighbouring molecule. The delta positive end of 1 molecule attracts the delta negative end of another molecule, creating a temporary electrostatic attraction.

why is a plasticiser used

to make a plastic more flexible

conditions for hydration

Steam, concentrated phosphoric acid, high temp, high pressure

conditions for dehydration

Concentrated sulfuric acid and heat

hydration of ethene advantages

Fast rate of reaction, continuous process, produces pure ethanol (high yield/purity).

hydration disadvantages

Uses non-renewable crude oil, requires high energy input (high temp/pressure —>expensive)

fermentation advantages

Uses renewable raw materials crops (glucose), low energy costs as low (30-40 degrees C) temp/pressure

fermentation disadvantages

slow reaction rate, batch process, produces impure ethanol (requires costly fractional distillation)