Organic Chemistry 1

Question 1

Alkene to Poly(alkene)

Answer 1

Addition polymerisation

The double bonds open up to make long chains of polymers

Question 2

Alcohols to alkene

Answer 2

Eliminating water from alcohols

Alcohol is mixed with an acid catalyst such as Conc. H3PO4 and is then heated

Question 3

Alcohol to aldehyde

Answer 3

Primary alcohols oxidise to aldehydes and then carboxylic acids

Potassium Dichromate (VI) Oxidising agent is used

You distil to get an aldehyde
You reflux for a carboxylic acid

Question 4

Alcohol to ketone

Answer 4

Secondary alcohols oxidise to form ketones

You need to reflux the secondary alcohol with acidified Dichromate (VI)

Question 5

Alcohol to halogenoalkane

Answer 5

React in nucleophillic substitution reactions to form halogenoalkanes

To make choloroalkanes:
You use PCl5 or HCl

To make bromoalkanes:
You need to react the alcohol with compounds containing the Br group. An acid catalyst is required 50% conc. H2SO4

To make iodoalkanes:
React the alcohol with PI3 made in situ by refluxing the alcohol

Question 6

Halogenoalkanes to amines

Answer 6

Warm halogenoalkane with excess alcoholic ammonia

Nucleophillic substitution

Ammonia swaps places with halogen to form amine

Question 7

Halogenoalkane to a Nitrile

Answer 7

Reflux halogenoalkane with Potassium Cyanide in ethanol

Nucleophillic sub

Question 8

Halogenoalkane to alcohols

Answer 8

React with aqueous KOH

React with hydroxide ions by nucleophillic sub under reflux

Question 9

Halogenoalkane to alkene

Answer 9

Halogenoalkane undergo elimination to form alkene

Warm alkali dissolved in ethanol is required

Needs to be heated under reflux

OH- acts a base to remove a H+ from halogenoalkane

Question 10

Alkene to halogenoalkane

Answer 10

Alkene undergo electrophiilic addition using hydrogen halides to form halogenoalkane

Question 11

Alkene to alkane

Answer 11

Hydrogenation

Requires nickel catalyst at 150 degrees

Question 12

Alkene to alcohol

Answer 12

Hydration by steam at 500 degrees

Required solid Phosphoric (V) acid catalyst

Question 13

Alkane to alkene

Answer 13

Thermal cracking

Zeolite catalyst at 95 degrees

Involves breaking the C-C bonds to form smaller hydrocarbons

Question 14

Alkane to halogenoalkane

Answer 14

Photochemical reaction using halogens in free radical substitution reactions

Initiation- radicals are made

Propagation- radicals are used and created

Termination- radicals are destroyed

Question 15

Homolytic fission

Answer 15

The bond breaks evenly and each bonding atoms receives one election from the bonding pair

Two electrically uncharged radicals are formed

Question 16

Heterolytic fission

Answer 16

The blonde brakes unevenly with one of the bonded atoms receiving both electrons from the bonded pair

Two different substances can be formed—

Question 17

Fractional distillation

Answer 17

• Crude oil is vaporised at around 350 degrees
• vaporised crude oil goes into a fractionating column and rises up through the trays. the largest hydrocarbons do not vaporise at all because their boiling points are too high. Instead they just run to the bottom to form a gooey residue
• as the crude oil vapour goes up the fractionating column it gets cooler because the Alkane molecules have different chain lengths therefore have different boiling points so each fraction condenses at different temperatures
• hydrocarbons with the lowest boiling points do not condense the drawn off as gases at the top of the column

Question 18

Harmful emissions produced by fuels

Answer 18

•Carbon monoxide:
Toxic gas which can affect the amount of oxygen being carried around your body

•Sulfur dioxide and Oxides of Nitrogen:
Acid rain is caused by burning fuels containing sulfur.

•Oxides of nitrogen are produced when the high pressure and temperature of a car engine cause nitrogen and oxygen in the air to react together. When it escapes into the atmosphere it dissolve into the air and is converted to nitric acid which can fall as acid rain

Question 19

Catalytic converters

Answer 19

Stay in a car exhaust and stops some pollutants from coming out

They get rid of pollutants by using a platinum catalyst to change them harmless gases

Question 20

Sigma bonds

Answer 20

Single covalent bonds in organic molecules are sigma bonds.

It’s formed when two orbitals overlap in a straight line giving the highest possible electron density between two nuclei

High electron density between nuclei means there is a string electrostatic force of attraction between nuclei and shared pair of electrons. Meaning they have a high bond enthalpy

Question 21

Pi bonds

Answer 21

Double bonds are made of sigma and pi bonds.

Pi bonds are formed when two loves of two orbitals overlap sideways

The electron density is spread above and below the nuclei causing the electrostatic attraction between nuclei and shared pair of electrons weaker. Making them have low bond enthalpy

Question 22

Double bonds

Answer 22

C=C bond and the atoms attached lie in the same plane- they’re planar

Atoms can not rotate around the C=C bond due to the way the p orbitals overlap and form pi bonds

However they can rotate any single bonds in the molecule

Restricted rotation around c=c is what cause alkene stock form steroisomers

Question 23

E/Z isomerism

Answer 23

E-isomer has the same groups positioned across the double bond

Z-isomer has the same groups either both above or both below the double bond

Atoms with higher atomic numbers are given higher priority

Question 24

Cis-Trans isomerism

Answer 24

Cis means the same groups are in the same side of double bond

Trans means the same groups are on opposite sides of the double bond