Chemistry 9701 · AS & A Level · Polymerisation

Polymerisation — practice question

Super-absorbent polymers are placed in the hydrogel category. They are usually produced by polymerising compound $K$ with sodium hydroxide in the presence of an initiator.
(a(i))[1]

Explain what the term polymerisation means.

(a(ii))[1]

What type of polymerisation is used in making hydrogels?

(a(iii))[3]

Describe the changes in chemical bonding that take place during the polymerisation of $K$.

(b)[1]

Compound $K$ has the common name acrylic acid. Suggest the systematic (chemical) name of $K$.

(c(i))[2]

Draw the structure of at least two repeat units of the polymer formed from acrylic acid, $K$, when it is mixed with NaOH.

(c(ii))[4]

The C-C-C bond angle in compound $K$ changes when the polymer is formed. State and explain how the C-C-C bond angle is different in a molecule of $K$ compared with the polymer.

(d(i))

Draw a detailed diagram of part of the polymer you drew in (c)(i) to show how it can take in a large volume of water.

(d(ii))[4]

A student added $0.10\,\text{g}$ of the polymer to $10\,\text{cm}^3$ of aqueous copper(II) sulfate solution. Predict, with a reason, what you would observe.

(e(i))[2]

Compound L, $\text{CH}_2=\text{CHCONH}_2$, can also be polymerised to make a super-absorbent polymer. Name the two functional groups in compound L.

(e(ii))[1]

Compound K can be changed into compound L by the two-step route below. Suggest a reagent for step 1.

(e(iii))[1]

What additional product is formed in step 2?

(e(iv))[1]

State the reagents and conditions needed to re-form K from L.

Worked solution & mark scheme

This 21-mark question has a full step-by-step worked solution and mark scheme. One marking point: A polymer is formed when many monomers join together

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