ACE Homework EQ's Flashcards
The key steps in the manufacture of poly(propene) from crude oil are shown.
For each step, name the process and state briefly the purpose of the process that leads to the formation of poly(propene). [6 marks]
Step 1: Fractional Distillation
-it separates the fractions of the crude oil mixture that have similar boiling points
Step 2: Cracking
-it breaks down the Naptha into smaller carbon chain molecules (alkanes and alkenes)
Step 3: addition polymerisation
-it joins the molecules of the propene together
Explain why poly(propene) is unreactive. [1 mark]
The molecule isn’t polar
Suggest why it is beneficial for some polymers to be biodegradable. [1 mark]
To prevent the build up of waste in landfill
State the general formula of an alkane containing n carbon atoms.
Deduce an expression for the Mr of an alkane in terms of n. [2 marks]
CnH2n+2
14n+2
Explain why nonane has a higher boiling point than 2,4-dimethylheptane. [2 marks]
-nonane is a more compact molecule
-so has more and stronger Van der Waals forces between the molecules
Explain how this nitrogen monoxide is formed. [2 marks]
-nitrogen and oxygen found in the air react together
-due to the high temperatures
Nonane can be cracked to form large quantities of propene. [1 mark]
Thermal cracking
Suggest why the combustion of fuel oil is likely to be incomplete. [1 mark]
It’s difficult to supply sufficient air/oxygen to the reaction
Identify a gas that may be present because of incomplete combustion.
Suggest why the use of electrostatic precipitators could be a hazard if this gas were present. [2 marks]
Carbon monoxide
It’s very flammable
State how nitrogen oxides could be formed during the manufacture of Portland cement. [1 mark]
Oxygen reacts with nitrogen in the air at high temperatures
Suggest why a kiln with a very fast air flow is likely to emit more sulfur dioxide than one with slower air flow but otherwise operating under the same conditions. [1 mark]
Less chance of a reaction of SO2 if the air flow is fast
