Organic chemistry Flashcards
What is crude oil?
Formed over millions of years from fossilised remains of plankton. Found in porous rocks in the earth’s crust. Crude oil is a definite resource that is used to produce fuels and other chemicals.
The larger the hydrocarbon…
- The more viscous it is
- The higher its boiling point
- The less volatile it is
- The less easily it ignites
Process of fractional distillation
- Crude oil heated
- The vapour moves up the fractionating column
- The top is colder than the bottom.
- Shorter hydrocarbons reach the top before they condense and are collected. Longer hydrocarbons molecules condense at higher temperatures and are collected lower down.
Alkanes properties
Saturated, contain only single bonds
Fairly unreactive but burn well
Formula= CnH2n+2
Shorter chain alkanes
Monkeys=methane
Eat=ethane
Peanut=propane
Butter=butane
Wha is produced in incomplete combustion?
Carbon monoxide. A colourless, odourless and toxic gas.
How is nitrogen oxide formed? And how they affect humans/buildings/animals?
Due to the high temperatures reached when fuels burn, nitrogen in the air can react with oxygen to for nitrogen oxides. These gases can cause respiratory problems in humans and react with rain water to form acid rain.
What is cracking?
Braking long chain hydrocarbons into shorter, more useful hydrocarbons.
What happens in steam cracking?
Hydrocarbons are mixed with steam.then heated up to 850 degrees c.
What happens in catalytic cracking?
- Hydrocarbons heated until they evaporate.
- Vapour passed over a hot aluminium oxide catalyst
- A thermal decomposition reaction takes place.
Cracking products
Short chain alkane and Alkenes. Alkenes can be used to make polymers.
What can be used to differentiate Alkenes and alkanes?
Bromine water. When an alkane is present, the bromine water doesn’t change colour and stays orange brown. When an Alkene is present the bromine water turns colourless.
