A substitution reaction in which an electrophile causes the first bond to break.
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What is a mechanism?
A diagrammatic representation of a reaction using curly arrows to show movement of electron pairs.
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What is unsaturated?
Containing at least one carbon-carbon multiple bond.
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What is a structural isomer?
Same molecular formula, different structural formula.
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What is a stereoisomer?
Same structural formula, different arrangement of atoms in space.
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what is E/Z isomerism?
Example of stereoisomerism, restricted rotation around double bond and requirement for 2 different groups to be attached to each carbon of C=C group.
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What are Cis-Trans isomers?
A special case of E/Z isomerism in which two of the substituent groups are the same.
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What is an electrophile?
A species that's attracted to an electron rich centre where it accepts a pair of electrons and forms a new covalent bond.
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What is heterolytic fission?
The breaking of a covalent bond where the shared pair of electrons split unequally, forming an anion and cation.
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What is the general formula for an alkene?
CnH2n.
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What is the general formula for a cycloalkene?
CnH(2n-2),
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What types of bond is the C=C double bond made up of?
a Sigma bond and a Pi bond.
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What type of bond are all single bonds?
Sigma bonds.
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How is the Pi bond formed?
By sideways overlap of adjacent p-oribitals above and below the bonding C atoms.
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What is the criteria for E/Z stereoisomerism?
1)Restricted rotation around C=C double bond.2)Each carbon in C=C double bond must be attached to 2 different atoms or groups.
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What is the criteria for Cis-Trans isomerism?
1)Meet criteria of E/Z.2)Two of the substituent groups are the same.
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How can the isomerism be determined when the elements attached to carbon are all different?
The two atoms with the greatest atomic mass on each carbon will be the ones that determine the isomerism.
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Why is the C=C bond reactive?
1)Pi bond is region of electron density- susceptible to electrophilic attack.2)Pi bond is weaker than sigma bond.
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Describe electrophilic addition.
1)Electrophile attracted to C=C bond, Pi bond breaks.2)The electrophile bonds with the carbon, and an intermediate forms,3)Carbon=+ and negative nucelophile remains.4)Nuclephile bonds with carbon.
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What is a intermediate with carbon often called?
A carbocation.
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Describe hydrogenation of alkenes.
1)React with hydrogen to produce alkane.2)Conditions=150 degrees and nickel catalyst.
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What is hydrogenation of alkenes used for?
In manufacture of margarine.
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Describe the reaction between alkenes and halogens.
1)React with halogen, e.g. Br,Cl etc.2)Room temperature and pressure.3)Produces alkane, e.g. 1,2, dibromoethane.
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Describe the reaction between alkenes and hydrogen halides.
1)React with Hydrogen halide e.g. HBr, HCl.2)Room temperature and pressure.3)Produces alkane, e.g. bromoalkane.
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What is the Markonvinkoff Rule?
The rule predicts that hydrogen will bond to a carbon that has the most hydrogen.
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Describe the reaction between an alkene and steam.
1)Reacts with steam (H2O).2)High temperature and pressure.3)Catalyst= phosphoric acid.4)Produces alcohol.
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What is the reaction between ethene and steam used for?
Production of ethanol.
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What is the atom economy of this reaction?
1)100%.2)Addition reaction.3)Only one product.4)No waste product.
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Other cards in this set
Card 2
Front
What is a mechanism?
Back
A diagrammatic representation of a reaction using curly arrows to show movement of electron pairs.
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