C9: Crude Oil and Fuels Flashcards
What are alkanes?
Saturated hydrocarbons meaning they have single covalent bonds between carbon atoms. Have general formula CnH2n+2.
What are the first 4 alkanes?
Methane - CH4
Ethane - C2H6
Propane - C3H8
Butane - C4H10
What are crude oils?
Finite resources found in rocks and are the remains of ancient biomass. They are mixtures of a very large number of compounds, often hydrocarbons.
What happens as the size of hydrocarbon molecules increase and they become longer chain?
- Boiling point increases.
- Volatility decreases (tendency to turn into a gas).
- Viscosity increases (how easily it flows).
- Flammability decreases.
What is fractional distillation?
It separates hydrocarbons based on their boiling points. Each fraction contains molecules with a similar number of carbon atoms.
Lower chain hydrocarbons such as petroleum are collected first and used as fuels as they can ignite more easily.
At the bottom of the fractionating column, longer chain hydrocarbons are collected as very thick liquids or solids.
What is the equation for complete and incomplete combustion of hydrocarbons?
Complete: Hydrocarbon + O2 —> Carbon Dioxide + Water
Incomplete: Hydrocarbon + O —> Carbon monoxide + Water
What is the test for carbon dioxide?
It turns limewater cloudy.
What is the test for water?
It turns blue cobalt chloride paper pink.
What is cracking?
It involves breaking down larger hydrocarbon molecules into smaller, more useful ones.
Either passed over a hot catalyst or mixed with steam and heated to high temperature.
What are alkenes?
They are unsaturated hydrocarbons that contain at least one double bond between carbon atoms. Have general formula CnH2n. They are generally more reactive than alkanes.
What is the test of alkenes?
Unsaturated hydrocarbons turn orange bromine watee colourless.
