Thin sheets of aluminium are used to wrap foodstuffs, e.g. chocolate. Plastic cling film used to wrap food is sometimes made from poly(chloroethene) or PVC, an addition polymer. The following terms are associated with material properties: electrical conductivity malleability lustre chemical inertness melting point (i) Explain the terms malleability and lustre. (ii) Select two of the five properties above that make aluminium a suitable material for wrapping food. (iii) An addition polymer is made by joining together many monomer units each of which contains a carbon-carbon double bond. Draw the structure of chloroethene, the monomer for making poly(chloroethene). (iv) Draw two repeating units of poly(chloroethene).

Leaving Cert Chemistry OPTION : Metals: Thin sheets of aluminium are use

Thin sheets of aluminium are used to wrap foodstuffs, e.g - Leaving Cert Chemistry - Question B - 2022

Question B

Thin sheets of aluminium are used to wrap foodstuffs, e.g. chocolate. Plastic cling film used to wrap food is sometimes made from poly(chloroethene) or PVC, an addit... show full transcript

Worked Solution & Example Answer:Thin sheets of aluminium are used to wrap foodstuffs, e.g - Leaving Cert Chemistry - Question B - 2022

Step 1

Explain the terms malleability and lustre.

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Answer

Malleability refers to the ability of a material to be hammered or pressed into thin sheets without breaking. This property allows metals like aluminum to be shaped easily, forming sheets that can be used for wrapping food products.

Lustre, on the other hand, is the shininess or sheen of a material, which signifies its ability to reflect light. Materials with high lustre can appear shiny and polished, enhancing their aesthetic value.

Step 2

Select two of the five properties above that make aluminium a suitable material for wrapping food.

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Answer

The two suitable properties of aluminium for wrapping food are:

Malleability - This property allows aluminum to be formed into thin sheets that fit around various shapes of food items.
Lustre - The shiny surface not only enhances the appearance of the packaging but also helps in reflecting light, potentially prolonging the shelf life of food.

Step 3

Draw the structure of chloroethene, the monomer for making poly(chloroethene).

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Answer

The structure of chloroethene (C2H3Cl) can be represented as follows:

 H   Cl
  \  /
   C=C
  /  \
 H    H

This structure shows the carbon-carbon double bond along with the chlorine atom attached to one of the carbon atoms.

Step 4

Draw two repeating units of poly(chloroethene).

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Answer

The repeating units of poly(chloroethene) can be illustrated as:

    Cl               Cl
   |                |
--C--           --C--
 |              |
 H             H

This shows the two repeating units where the chlorine is attached to the alternating carbon atoms in the polymer chain.

Thin sheets of aluminium are used to wrap foodstuffs, e.g - Leaving Cert Chemistry - Question B - 2022

Worked Solution & Example Answer:Thin sheets of aluminium are used to wrap foodstuffs, e.g - Leaving Cert Chemistry - Question B - 2022

Explain the terms malleability and lustre.

Select two of the five properties above that make aluminium a suitable material for wrapping food.

Draw the structure of chloroethene, the monomer for making poly(chloroethene).

Draw two repeating units of poly(chloroethene).

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