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Organic Reactions
Substitution, Addition, Elimination and Polymerisation
Question | Answer |
---|---|
What is a substitution reaction? | A substitution reaction is a chemical reaction in which an atom or group of atoms in a molecule is replaced by another atom or group of atoms. |
What is a photochemical reaction? | A photochemical reaction requires UV light to be completed. |
What are the 3 steps in the substitution reaction between Chlorine and Methane | Initiation, Propagation and Termination |
What is homolytic fission? | Homolytic fission is when a bond breaks in such a way that both atoms keep one of the electrons from the bond |
How do we know that the substitution reaction between Chlorine and Methane is a photochemical reaction? | It will not occur in the dark |
What is a free radical? | A free radical is an atom or group of atoms with an unpaired electron. |
What free radical is formed during the propagation stage of the substitution reaction between Chlorine and Methane? | Methyl free radcal |
What are the 3 possible outcomes of the termination stage of the substitution reaction between Chlorine and Methane? | 1: Two Chlorine free radicals bond to form a Chlorine molecule 2: A Chlorine and a Methyl free radical bond to form a chloromethane molecule. 3: Two methyl free radicals bond to form ethane. |
What happens in the substitution reaction between Chlorine and Methane if we add tetramethyl lead to the reaction? | There is an increase in the rate of reaction as tetramethyl lead decomposes to form methyl free radicals |
Alternative name for the substitution reaction between Chlorine and Methane? | Free radical substitution reaction |
What are fully halogenated alkanes used for? | They are fire resistant and are added to other compounds to make them flame resistant also. |
What fully halogenated alkane has had a dangerous reaction with the environment | CFCs are halogenated alkanes. They can damage the Ozone layer. They have since been replaced with Hydro Chloro Fluoro Carbons (HCFCs) |
What is an addition reaction? | An addition reaction is one in which two substance react together to form a single substance? |
What is a common industrial use of addition reactions? | Liquid oils are solidified by breaking open some of the double bonds and adding hydrogen. This is known as Hydrogenation. The amount of Hydrogen added determined the hardness of the material like butter. |
Is the addition of Ethene and Bromine a photochemical reaction? | No, it can occur in the dark |
What is heterolytic fission? | This is the breaking of a bond where one atom gets both electrons. |
What ion is formed when a Bromine free radical bonds with the Ethene? | Carbonium Ion |
Alternative name for the addition reaction of ethene and bromine? | Ionic addition reaction as it involves the addition of ions. |
What is an elimination reaction? | An elimination reaction is one in which a small molecule is removed from a larger molecule to leave a double bond in the large molecule. |
What is the name for an elimination reaction where water is the molecule removed? | Dehydration reaction |
Give an example of an elimination reaction? | Ethene is produced by the elimination of water from ethanol. |
What is a polymerisation reaction? | The manufacture of polymers by the joining together of many small molecules called monomers. |
Give an example of a polymer and its monomer? | Ethene is a monomer used to create polyethene |
How is PVC created? | Cl gas is reacted with ethene to create the monomer chloroethene. This monomer is then used to create Poly Vinyl Chloride. |
Uses for polythene? | Polythene is used in the manufacture of plastic bags, bowls, lunch boxes, food wrapping, washing up liquid bottles and buckets |