Organic Chemistry (Alkanes, Alkenes, Crude Oil) Flashcards
Explain why all of these compounds are described as hydrocarbons (2)
The compounds all contain hydrogen and carbon atoms only
Why are B and E described as unsaturated? (1)
Compounds B and E have double bonds
Which letter represents the first member of the homologous series of alkanes? (1)
A
Which letter represents the compounds that have the empirical formula CH2? (1)
B, E, F
Why does F not decolourise bromine water? (1)
Compound F has no double bonds, but only has single bonds therefore is saturated and does not decolourise bromine water.
Identify which of these fractions has the darkest colour (1)
- fuel oil
- gasoline
- kerosene
Fuel oil
Identify which of these fractions has the highest boiling point (1)
- fuel oil
- gasoline
- kerosene
Fuel oil
Identify which of these fractions contains molecules with the fewest carbon atoms (1)
- fuel oil
- gasoline
- kerosene
Gasoline
Name a catalyst used in industry for cracking. (1)
Alumina
One reaction that occurs in cracking involves the conversion of one molecule of hexadecane into one molecule of octane and two molecules of an alkene. Complete the equation for this reaction (2)
C16H34 –> C8H18 + ___
C16H34 –> C8H18 + C4H8 + C4H8
Give three reasons why cracking is carried out. (3)
There is a greater supply of long-chain hydrocarbon molecules, and there is a higher demand for short-chain hydrocarbons than long-chain hydrocarbons Therefore, cracking is carried out where alkenes are used to make polymers.
One of the compounds sometimes present in crude oil has the formula C6H12S. Explain why it is important to remove this compound from a fuel (2)
When burned, this compound will form sulfur dioxide which can cause environmental problems like acid rain
Which fraction has the lowest boiling point? (1)
Refinery gases
Which fraction is the most viscous? (1)
Bitumen
Some fractions containing long-chain hydrocarbons are cracked. The cracking of octadecane (C18H38) produces octane (C8H18) and one other product. Write a chemical equation for this cracking reaction. (1)
C18H38 –> C8H18 + C10H20