Condensation polymerisation

What are the organic products of the acid hydrolysis of CH₃CH₂CONHCH₃?

A CH₃CH₂COO^– + CH₃NH₃⁺

B CH₃CH₂COOH + CH₃NH₃⁺

C CH₃CH₂COOH + CH₃NH₂

D CH₃CH₂COO^– + CH₃NH₂

1-Chlorobut-2-ene and 3-hydroxybutanoic acid can both form polymers.

Draw two repeat units of each of the polymers formed.

State the type of polymerisation reaction that takes place for each compound.

The disposal of polymers containing chlorine is a major challenge.

Suggest why a polymer made from monomers containing chlorine, such as 1-chlorobut-2-ene, is difficult to dispose of by incineration.

The polymer formed from 3-hydroxybutanoic acid can be hydrolysed. This makes the polymer biodegradable.

Suggest what feature in the structure of this polymer allows this hydrolysis.

1,6-Diaminohexane, H₂N(CH₂)₆NH₂, reacts with hexanedioyl dichloride, Cl OC(CH₂)₄COCl to form a polyamide and one other product.

What is the other product formed in this reaction?

A HC l

B H₂O

C CO

D NH₃

This question is about carboxylic acids and esters.

Short-chain carboxylic acids, such as methanoic acid, HCOOH, are soluble in water.

Explain, with a labelled diagram, how HCOOH interacts with water when it dissolves.

Ester F has the structure shown below.

What is the systematic name for this ester?

Ester F can be prepared from a carboxylic acid in two steps.

Step 1 The carboxylic acid is converted into an acyl chloride.

Step 2 The acyl chloride is converted into ester F.

Write equations for Step 1 and Step 2.

Show organic compounds as structures.

Step 1

Step 2

The repeat unit of a polyester is shown below.

Draw the structures of monomers required to form this polyester.

The compound below contains an ester and an amide group.

Draw the structures of the organic products formed by the complete alkaline hydrolysis of this compound using NaOH(aq).

-Amino acids have the general formula RCH(NH₂)COOH.

The R group in an -amino acid contains C and H only.

This R group has a molar mass of 91 g mol^–1.

A polymer is formed from 500 molecules of this -amino acid.

Determine the molar mass of this polymer.

Give your answer to the nearest whole number.

molar mass of polymer =........ g mol^–1

This question is about aromatic compounds containing the –COOH and –OH functional groups.

Salicylic acid, shown below, is used in the manufacture of some important medicines.

Salicylic acid

Complete the flowchart for reactions of salicylic acid, by adding the organic products in each

PAS, shown below, is an antibiotic used to treat several diseases including tuberculosis (TB).

A student predicts that PAS could polymerise to form a polymer containing both ester and amide linkages.

Draw a section of this polymer.

The section should contain one amide and one ester linkage, which should be displayed.

For the treatment of TB, the maximum daily dosage of PAS that should be prescribed is 300 mg per kg of body mass.

A child weighs 20.0 kg.

Calculate the number of PAS molecules in the maximum daily dosage of PAS for this child.

This question is about -amino acids.

The general formula of an -amino acid is RCH(NH₂)COOH.

Most -amino acids show optical isomerism.

Explain the term optical isomerism.

The -amino acid valine has the R group of –CH(CH₃)₂.

What is the systematic name of valine?

Draw diagrams to show 3D structures of the optical isomers of valine.

How many optical isomers are possible for compound E ?

A student hydrolyses compound E with dilute hydrochloric acid, HC l (aq).

Draw the structures of the organic products formed by this hydrolysis.

This question is about compounds that contain the carboxylic acid functional group.

Carboxylic acids react with alkalis, metals and carbonates to form salts.

Write full equations for the following three reactions. Show structures for organic compounds.

• the reaction of propanoic acid with aqueous potassium hydroxide:

• the reaction of aqueous methanoic acid with magnesium:

• the reaction of the –amino acid, aspartic acid (R=CH₂COOH), with an excess of aqueous sodium carbonate, Na₂CO₃:

This part is about polymers derived from carboxylic acid monomers.

Poly(pent-3-enoic acid) is an addition polymer.

Draw the structure of pent-3-enoic acid and two repeat units of this polymer.

Butanedicarboxylic acid and 1,4-dihydroxy-2-methylbenzene react to form a condensation polymer.

Draw one repeat unit of this condensation polymer.

Three repeat units of a condensation polymer are shown below.

Draw the structure of the monomer required to form this polymer.

A polymer is formed from 400 molecules of 2-aminopropanoic acid.

Draw one repeat unit of this polymer.

What is the relative molecular mass, M_r, of the polymer?

This question is about haloalkanes and polymers.

Freon-13, is a CFC with the molecular formula CCl F₃. In the upper atmosphere, the presence of Freon-13 can lead to ozone depletion.

Explain, with the aid of equations, how Freon-13 can lead to this ozone depletion.

Use ‘dots’ (•) to show the position of unpaired electrons.

An oligomer is a polymer with a low molecular mass and a small number of repeat units.

An oligomer made from 2-chloro-1,1,2-trifluoroethene is used as a lubricating oil.

Draw the repeat unit of this oligomer.

The boiling point of the lubricating oil can be increased by increasing the number of repeat units.

Explain this statement.

A polymer can be made from the monomers:

• 1,4-diaminobutane

• benzene-1,4-diacyl dichloride.

Draw the structures of these monomers and one repeat unit of the polymer.

Alcohols can be used to prepare organic compounds with different functional groups.

HO(CH₂)₄OH can be oxidised to form HOOC(CH₂)₂COOH.

State the reagents and conditions and write an equation for this oxidation.

In the equation, use [O] for the oxidising agent.

Reagents and conditions:........

Equation:

HOOC(CH₂)₂COOH is soluble in water.

Explain, using a labelled diagram, why HOOC(CH₂)₂COOH is soluble in water.

HOOC(CH₂)₂COOH and HO(CH₂)₄OH react together to form polymer E.

Draw one repeat unit of polymer E.

The functional groups should be clearly displayed.

Governments are encouraging the development of biodegradable polymers to reduce dependency on persistent plastic waste derived from fossil fuels.

Polymer E is a biodegradable polymer.

Suggest why polymer E is able to biodegrade.

This question is about esters.

The structure of ester A is shown below.

What is the systematic name of ester A ?

Name the type of reactions of ester A shown in (ii).

A polyester is formed from 200 molecules of 4-hydroxybenzoic acid.

What is the relative molecular mass, M_r, of the polyester?

M_r =........ g mol⁻¹

* A student intends to synthesise ester C.

Plan a two-stage synthesis to prepare 12.75 g of ester C starting from 2-methylpropanal, (CH₃)₂CHCHO. Assume the overall percentage yield of ester C from 2-methylpropanal is 40%.

In your answer include the mass of 2-methylpropanal required, reagents, conditions and equations where appropriate.

Purification details are not required.

This question is about benzene.

Over time, the Kekulé and delocalised models have been used to describe the bonding and structure of a benzene molecule.

Describe, in terms of orbital overlap, the similarities and differences between the bonding in the Kekulé model and the delocalised model of benzene.

Experimental evidence led to the general acceptance of the delocalised model over the Kekulé model.

Describe two pieces of evidence to support the delocalised model of benzene.

Benzene can be used as the starting material for the synthesis of compounds D and E, shown below.

In the diagrams C₆H₅ is a phenyl group.

Compounds D and E can be converted into polymers.

Draw two repeat units of these polymers.

Two repeat units of polymer formed from D

Two repeat units of polymer formed from E

State the type of polymer formed from compounds D and E.

From compound D........

From compound E........

In the synthesis of compounds D and E, benzene is first reacted with ethanoyl chloride, CH₃COCl, to form phenylethanone, shown below.

The reaction takes place in the presence of aluminium chloride, Al Cl₃, which acts as a catalyst.

In the mechanism for this reaction,

• ethanoyl chloride first reacts with aluminium chloride to form the CH₃–C⁺=O cation

• the CH₃–C⁺=O cation then behaves as an electrophile.

Complete the mechanism for the reaction.

Include equations to show the role of the Al Cl₃ catalyst, relevant curly arrows and the structure of the intermediate.

Formation of electrophile........

Regeneration of catalyst........

Complete the flowchart for the synthesis of compounds D and E from phenylethanone.

The general formula of an -amino acid is RCH(NH₂)COOH.

The -amino acid cysteine (R = CH₂SH) shows optical isomerism.

Draw 3-D diagrams to show the optical isomers of cysteine.

The -amino acid lysine (R = (CH₂)₄NH₂) reacts with an excess of dilute hydrochloric acid to form a salt.

Draw the structure of the salt formed in this reaction.

-Amino acids can react to form proteins.

A short section of a protein chain is shown below.

A student hydrolyses the protein with hot NaOH(aq).

Draw the structures of the organic products formed from this section of the protein.

This question is about aromatic carboxylic acids and their derivatives.

The concentration of ester K in the cosmetic product is 9.13 × 10⁻² g dm⁻³.

Using the results, calculate the concentration, in mol dm⁻³, of ester M in the cosmetic product.

Give your answer to two significant figures.

concentration of ester M =........ mol dm⁻³

This question is about organic compounds containing nitrogen.

Sodium cyanide, NaCN, can be reacted with many organic compounds to increase the length of a carbon chain.

1-Chloropropane, CH₃CH₂CH₂Cl, reacts with ethanolic sodium cyanide by nucleophilic substitution.

Outline the mechanism for this reaction.

Include curly arrows, relevant dipoles and the structure of the organic product.

Compound G is used to synthesise compounds H and I as shown in the flowchart below.

Complete the flowchart showing the structure of compound G and the formulae of the reagents for Reaction 2 and Reaction 3.

Compound H reacts with dilute hydrochloric acid to form a salt.

Explain why compound H can react with dilute hydrochloric acid and suggest a structure for the salt formed.

Explanation........

Structure

Compound I is the monomer for the biodegradable polymer J.

Draw two repeat units of polymer J and suggest a reason why it is biodegradable.

The repeat unit of Nylon 6,6 is shown below.

Draw the structures of two monomers that can be used to form Nylon 6,6.

A sample of Nylon 6,6 has a relative molecular mass of 21500.

Estimate the number of repeat units in the sample.

Give your answer as a whole number.