Alkanes and isomerism Flashcards
(27 cards)
What is meant by the term Hydrocarbon?
Compounds containing hydrogen and carbon only.
Give the name of the substance from which alkanes are obtained.
Crude oil
Give the name of the process from which paraffin, petrol, bitumen, naphtha is obtained
Fractional distillation
Sate the meaning of the term structural isomers.
Compounds with the same molecular formula but different structural formula.
State two characteristics of a homologous series.
Same General formula, Chemically similar / same (chemical) reactions, Same functional group, Trends in physical properties.
Name and outline the technique used to separate isooctane from a mixture of octane and isooctane.
Fractional or simple distillation, the one with lower boiling points boils first (or reaches the top of the column first) this then condenses and collects.
Outline how different fractions are obtained by fractional distillation.
Crude oil is heated to vaporise it, the vapour passes into fractionating column, top of tower is cooler than bottom or negative temperature gradient, fractions separated by boiling points.
Sate the meaning of the term functional group isomers.
Same molecular formula, but different functional group.
Explain why the melting point of straight chain alkanes increase with size.
More Van Der Waals’ forces between molecules.
What is meant by the term Chain isomers?
Compounds with the same molecular formula but different arrangement of the carbon skeleton.
What is meant by the term position isomers?
Compounds with the same molecular formula but different structures due to different positions of the same functional group on the same carbon skeleton.
What are the products of complete combustion?
Water and Carbon dioxide
What are the products of incomplete combustion?
Water, Carbon (soot), Carbon monoxide
What are the environmental problems of Carbon dioxide and water?
These are greenhouse gases and they contribute to Global warming.
What is a problem of carbon (soot)?
Exacerbates asthma/ breathing problems/ damages lungs/ smog/ smoke/ global dimming.
Explain how oxides of nitrogen are formed.
Nitrogen and oxygen (from air) react at high temperatures.
Explain why the sulphur compounds found in crude oil should be removed from the fractions before they are used for central heating fuel.
SO2 is produced from the combustion and this causes acid rain.
What is a structural formula?
A formula that shows the arrangement of atoms in the molecule of a compound. CH3CH2CH3.
How is sulphur dioxide removed from power stations?
Neutralise with calcium oxide (flue gas desulphurisation).
Write an equation to show how carbon monoxide and nitrogen oxides react together in a catalytic converter.
2CO + 2NO → 2CO2 + N2
Identify a catalyst used in a catalytic converter.
Platinum, Palladium or Rhodium.
Why do blockages in air intakes affect the performance of engines?
Less energy given out by the fuel to burn more fuel to get the same energy / increased costs due to need to use more fuel.
Explain the main economic reason why alkanes are cracked.
To produce substances which are (more) in demand.
State why a high temperature is needed for cracking reactions to occur.
To break bonds.
