C7-Organic Chemistry Flashcards
What is crude oil made of?
A mixture of many different compounds-mostly hydrocarbons containing only hydrogen and carbon atoms
How are different hydrocarbons seperated?
Via fractional distillation
Are alkanes saturated or unsaturated and why?
Saturated-contain as many hydrogen atoms as possible in their molecules
what are the first 4 alkanes?
- Methane
- Ethane
- Propane
- Butane
What is the formula for alkanes?
CₙH₂ₙ₊₂
As the size of the hydrocarbon increases what happens to the….
* Boiling point?
* Volatility?
* Viscosity?
* Flammability?
- Increases
- Decreases
- Increases
- Decreases
What does volatility mean?
How easily something turns into a gas
In a fractioning column, where is it the hottest?
At the bottom
What is the order of fractions from the top of the fractioning column down?
- Refinery gas
- Petrol
- Kerosene
- Diesel
- Residue
What is the formula for complete combustion?
Hydrocarbon + Oxygen –> Carbon Dioxide + Water
How can we test the gases formed in complete combustion of a hydrocarbon?
Carbon dioxide turns limewater cloudy and water turns blue cobalt chloride paper pink.
What does incomplete combustion form?
Carbon monoxide (a toxic gas)
Why do we crack hydrocarbons?
The heavier fractions from fractional distillation of crude oil are not in high demand-they can be broken down to form shorter chains.
How is cracking carried out?
By passing alkane vapours over a hot catalyst-this is an example of thermal decomposition-forming 1 alkane and 1+ alkenes
How can we test for an unsaturated hydrocarbon (alkene)?
By seeing if it turns orange bromine water colourless
What are the first 4 alkenes?
- Ethene
- Propene
- Butene
- Pentene
What is the formula for alkenes?
CₙH₂ₙ
What is the functional group of alkenes?
C=C
What is a family of organic compounds with the same functional group called?
A homologous series
What makes alkenes far more reactive than alkanes?
The carbon-carbon double bond
How do alkenes react with halogens?
Use the example of ethene and bromine.
Ethene + Bromine –>dibromoethane