Topic 5: Alkenes

Know the general formula of alkenes and understand that alkenes and cycloalkenes are hydrocarbons which are unsaturated (have a carbon-carbon double bond which consists of a σ bond and a π bond).

Use —the general formula of alkenes and understand that alkenes and cycloalkenes are hydrocarbons which are unsaturated (have to connect the rule to the data and decision in the question.

This matters because —the general formula of alkenes and understand that alkenes and cycloalkenes are hydrocarbons which are unsaturated (have determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the general formula of alkenes and understand that alkenes and cycloalkenes are hydrocarbons which are unsaturated (have to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: use the formula and units given in the question, show the substitution and interpret the result; the calculation alone is not the conclusion.

Be able to explain geometric isomerism in terms of restricted rotation around a C=C double bond and the nature of the substituents on the carbon atoms.

Use —geometric isomerism in terms of restricted rotation around a c=c double bond and the nature of the substituents on to connect the rule to the data and decision in the question.

This matters because —geometric isomerism in terms of restricted rotation around a c=c double bond and the nature of the substituents on determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —geometric isomerism in terms of restricted rotation around a c=c double bond and the nature of the substituents on to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —Geometric isomerism in terms of restricted rotation around a C=C double bond and the nature of the substituents on is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand the E–Z naming system for geometric isomers and why it is necessary to use this when the cis- and trans- naming system breaks down.

Use —the e–z naming system for geometric isomers and why it is necessary to use this when the cis- and trans- naming system to connect the rule to the data and decision in the question.

This matters because —the e–z naming system for geometric isomers and why it is necessary to use this when the cis- and trans- naming system determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the e–z naming system for geometric isomers and why it is necessary to use this when the cis- and trans- naming system to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The E–Z naming system for geometric isomers and why it is necessary to use this when the cis- and trans- naming system is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to describe the reactions of alkenes, limited to: i the addition of hydrogen, using a nickel catalyst, to form an alkane ii the addition of halogens to produce a di-substituted halogenoalkane iii the addition of hydrogen halides to produce mono-substituted halogenoalkanes iv the addition of steam, in the presence of an acid catalyst, to produce alcohols v oxidation of the double bond by acidified potassium manganate(VII) to produce a diol.

Use —the reactions of alkenes to connect the rule to the data and decision in the question.

This matters because —the reactions of alkenes determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the reactions of alkenes to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The reactions of alkenes is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Know the qualitative test for a C=C double bond using bromine or bromine water.

Use —the qualitative test for a c=c double bond using bromine or bromine water to connect the rule to the data and decision in the question.

This matters because —the qualitative test for a c=c double bond using bromine or bromine water determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the qualitative test for a c=c double bond using bromine or bromine water to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The qualitative test for a C=C double bond using bromine or bromine water is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to describe the mechanism (including diagrams), giving evidence where possible, of: i the electrophilic addition of bromine and hydrogen bromide to ethene ii the electrophilic addition of hydrogen bromide to propene Use of the curly arrow notation is expected – the curly arrows should start from either a bond or from a lone pair of electrons. Knowledge of the relative stability of primary, secondary and tertiary carbocation intermediates is expected.

Use —the mechanism (including diagrams), giving evidence where possible, of: i the electrophilic addition of bromine and hydrogen to connect the rule to the data and decision in the question.

This matters because —the mechanism (including diagrams), giving evidence where possible, of: i the electrophilic addition of bromine and hydrogen determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the mechanism (including diagrams), giving evidence where possible, of: i the electrophilic addition of bromine and hydrogen to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The mechanism (including diagrams), giving evidence where possible, of: i the electrophilic addition of bromine and hydrogen is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Be able to describe the addition polymerisation of alkenes and draw the repeat unit given the monomer, and vice versa.

Use —the addition polymerisation of alkenes and draw the repeat unit given the monomer, and vice versa to connect the rule to the data and decision in the question.

This matters because —the addition polymerisation of alkenes and draw the repeat unit given the monomer, and vice versa determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —the addition polymerisation of alkenes and draw the repeat unit given the monomer, and vice versa to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —The addition polymerisation of alkenes and draw the repeat unit given the monomer, and vice versa is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.

Understand how chemists limit the problems caused by polymer disposal by: i developing biodegradable polymers ii removing toxic waste gases produced by the incineration of polymers.

Use —how chemists limit the problems caused by polymer disposal by: i developing biodegradable polymers ii removing toxic waste to connect the rule to the data and decision in the question.

This matters because —how chemists limit the problems caused by polymer disposal by: i developing biodegradable polymers ii removing toxic waste determines what can be inferred or chosen; begin with the stated conditions and keep the conclusion tied to the evidence.

Example: apply —how chemists limit the problems caused by polymer disposal by: i developing biodegradable polymers ii removing toxic waste to one small, clearly defined case, show the key step or comparison, and explain the result in words.

Boundary: —How chemists limit the problems caused by polymer disposal by: i developing biodegradable polymers ii removing toxic waste is not a universal recommendation. Check the syllabus scope, assumptions, units and the limits of the evidence before generalising.