Organic chemistry

Question 1

What is the purpose of :

• fractional distillation
• reforming
• cracking

Answer 1

Fractional distillation= Separating liquid mixture (crude oil) via boiling points and condensing
Cracking= breaking down long chain hydrocarbons into short chain hydrocarbons (creates a new alkane and alkene)
reforming= convert straight-chain alkanes into branched chain and cyclic alkanes by heating using a catalyst

Question 2

What is an additional product of reforming ?

Answer 2

Hydrogen

Question 3

What is the most common use of alkanes?

Answer 3

Fuels

Question 4

What type of reactions do alkanes undergo?

Answer 4

Substitution reactions

Question 5

What are the conditions for substitution reactions to occur in alkanes? Why must these conditions be present?

Answer 5

Mixture must be exposed to ultra violet (UV) light or sunlight, this doesn’t affect the alkane, however, it does break the break the bonds of the halogen molecule(homolytic fission) making 2 halogen radicals

Question 6

Name and define the 7 different types of reactions we encounter in organic chemistry

Answer 6

substitution: a species is replaced by another
addition: joining 2 or more molecules together to form a larger molecule
polymerisation: joining lots of simple molecules to form a giant molecule
elimination: small group of atoms break away from a larger molecule
hydrolysis: Splitting molecules with water (H+ and OH- ions)
oxidation: reaction in which species lose electrons
reduction: reaction in which species gain electrons

Question 7

How can we go from a halogenoalkane to an alcohol?

Answer 7

1) hydrolysis - mix halogenoalkane with water and warm up

2) heating halogenoalkane with aqueous potassium hydroxide under reflux

Question 8

If we heat ethanoic potassium hydroxide and a halogenoalkane under reflux, what kind of reaction is this and what products are expected?

Answer 8

This is an elimination reaction (as the ethanol makes the OH- ion actas a base) and we produce an alkene

Question 9

What do we react with a halogenoalkane in order to form a nitrile?

Answer 9

potassium cyanide dissolved in ethanol and heated under reflux

Question 10

If we add excess Ammonia in a sealed tube and heat it with a halogenoalkane, what do we get?

Answer 10

A primary amine

Question 11

What do we add to a hydrolysis reaction, in order to measure the rate of reaction?

Answer 11

Silver nitrate solution

Question 12

what is heterolytic fission?

Answer 12

Breaking of a bond in which the electrons aren’t fairly distributed - one element gets more than the other, resulting in charged ions

Question 13

what is homolytic fission?

Answer 13

Breaking of a bond in which the electrons are fairly distributed.