Organic Chemistry Flashcards
What is a hydrocarbon ?
A hydrocarbon is any compound that is formed by only carbon and hydrogen atoms
What is an Alkane ?
The most simple type of hydrocarbon you can get .
Solid to be saturated - means that these atoms are helps together by single bonds
What do the saturated molecules contain ?
They contain : a carbon carbon covalent bond (c-c)
Alkanes are part of what series ?
Homologous series - a group of organic compounds that react in a similar way .
Alkanes are saturated compounds
Each carbon atom forms what type of bond ?
4 single covalent bonds
What are the first 4 alkanes ?
Methane - CH4
Ethane - C3H8
Propane - C2H6
Butane -
What happens as the length of the carbon chain changes ?
The properties of the hydrocarbon changes
The shorter the carbon chain …
- Lower boiling point
- Higher volatility
- Low viscosity (very runny )
- Highly flammable
The longer the carbon chain ….
- Higher boiling point
- Lower volatility
- Higher viscosity ( thick )
- Lower flammability
Hydrocarbons with a lower carbon chain are …
More volatile - lower boiling points
A shorter carbon is also more …
Flammable the hydrocarbon is
The properties of the hydrocarbons affect how they can be used for fuels …. For example :
Shorter chain hydrocarbons with lower boiling points are used as bottle gases - stored under pressure as liquids in bottles
What is viscosity ?
How easily it flows
What is volatility ?
How likely to turn into a gas it is
What is fractional distillation ?
Separation of a liquid mixture into fractions differing in boiling points , typically using a fraction sing column
Explained steps involved in the fractional distillation of crude oil
Crude oil enters the fractions get column as a vapour
As you go up the temperature decreases
Gases condense at their boiling point
Different fractions collected as liquids at the different levels
Fractions with lower boiling points collect at the top
Fractions with higher boiling points collect at the bottom
When burning hydrocarbons we burn them in plenty of air and the energy transfers to where?
The surroundings
The most common hydro carbon burnt is propane
What is the word equation
Propane + Oxygen = carbon dioxide + water
Why do we crack hydrocarbons ?
To make much smaller and much more useful hydrocarbons - these are in high demand
Longer chain are not as useful
How do we crack hydrocarbons ?
1 . Heated vapour is then passed over a hot catalyst
2 . Mixed with steam and heated to a high temp ( thermal decomposition )
What is an Alkene ?
An Alkene tells us they are unsaturated. They have at least on double carbon bond ( c=c )
What is incomplete combustion ?
Incomplete combustion will occur when there is not enough oxygen to allow the fuel to react completely to produced carbon dioxide and water
What is the difference between a saturated and an unsaturated hydrocarbon ?
Alkane - ( c-c ) single carbon bond ( saturated )
Alkene - (c=c) double carbon bond ( unsaturated )
What is the test to find out if a hydrocarbon is saturated or unsaturated ?
A positive test for an UNSATURATED hydrocarbon is that it turn orange bromine water colourless where as if it was SATURATED it would remain orange
(Alkanes don’t react with water ) - therefore we can see what the hydrocarbon is
