Hydrocarbons Flashcards
(25 cards)
What are hydrocarbons?
Compounds made only of hydrogen and carbon atoms.
What is the simplest hydrocarbon?
Methane (CH₄).
What are the two main types of hydrocarbons?
Alkanes (saturated) and alkenes (unsaturated).
What is the general formula for alkanes?
CₙH₂ₙ₊₂
What is the general formula for alkenes?
CₙH₂ₙ
What is the difference between alkanes and alkenes?
Alkanes are saturated (only single bonds); alkenes are unsaturated (contain a double bond).
How are hydrocarbons found?
In crude oil and natural gas.
What is crude oil?
A mixture of hydrocarbons, mostly alkanes, that can be refined into useful products.
What is fractional distillation?
A process used to separate crude oil into different fractions based on boiling points.
At what temperature is crude oil heated for fractional distillation?
Around 350°C.
What are the fractions produced from crude oil?
Gases, petrol, kerosene, diesel oil, heavy fuel oil, and bitumen.
What happens to the temperature during fractional distillation?
It decreases as you move up the column.
What happens in the distillation column?
The vaporised hydrocarbons cool and condense at different heights depending on their boiling points.
Which hydrocarbons have the lowest boiling points?
The smallest molecules (e.g., gases like methane, ethane).
Which hydrocarbons have the highest boiling points?
The largest molecules (e.g., bitumen).
What is the fraction that is used for making petrol?
The fraction with boiling points between 30°C and 200°C.
What is cracking?
A process used to break down large hydrocarbons into smaller, more useful ones.
What type of hydrocarbons does cracking produce?
Alkenes and smaller alkanes.
What is catalytic cracking?
Cracking using heat and a catalyst, typically at around 500°C.
Why is cracking important?
It increases the supply of more valuable alkenes and smaller alkanes like petrol.
What is a common use of the fraction called naphtha?
It is used to make chemicals and plastics.
What is bitumen used for?
It is used for making road surfaces and roofing materials.
What is the environmental impact of using fossil fuels?
They release carbon dioxide, contributing to global warming and climate change.
What is the main component of natural gas?
Methane (CH₄).
