Hydro carbonds

Alkane

* Has only single bonds
* It is saturated
* ends with the prefix -ane
* (Methane, Ethane, Propane, Butane, Pentane)
* Cn H2n+2

Alkene

• They are unsaturated hydrocarbons.

• Has one carbon double bond .

• Ends with the prefix -ene

• (ethene, propane, butene, pentene)

• CnH2n

Alkane formula

Cn

\+

H2n+ 2

Alkene formula

Cn + H2n

What does viscoucity mean?

having a thick, sticky consistency between solid and liquid; having a high __viscosity__.

what is the homologus series?

A group of compounds which reacts in a similar way

What does saturated mean?

Only contains single bonds

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(a hydro carbon where every bond between atoms is a single bond)

What does unsaturated mean?

contains double bonds

What is a double bond?

A type of covalent bond where 4 electrons are shared between 2 atoms

What is cracking?

A thermal decomposition reaction tht breaks hydrocarbonds down

What happens in the combustion of hydro carbon fuels?

* They release energy.
* During combustion, they get oxidized.
* The complete combustion of a hydrocarbon produces carbon dioxide and water.

How is the boiling point related to the positioning of the hydro cabon in a fractional column?

As you move up a fractionating column the temperature decreases, so the compounds with higher boiling points come off lower down the column.

How is the boiling point effected b the size of the hydro carbon?

* As the molecules get larger, the **intermolecular forces** of **attraction** between the molecules becomes greater as there are more electrons in the molecules and greater **surface area contact** between them
* This means that more heat is needed to separate the molecules, hence with increasing molecular size there is an **increase** in **boiling point**

How is viscosity effected by the size of the hydro carbon?

* Viscosity increases with increasing chain length
* This is due to the increased intermolecular forces of attraction as molecular size increases

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Increased viscosity means that longer chained alkanes are useful as lubricants in machinery as they are less likely to burn and function to reduce friction between moving parts

How is flammability effected by the size of the hydro carbon?

* Smaller hydrocarbon molecules are more **flammable** and are easier to ignite than larger molecules
* This makes them very useful as fuels, releasing large amounts of energy when they burn

are alkanes more reactive or alkenes? and why.

alkenes (which is why it reacts with bromine water)

* due to the presence of the carbon carbon double bond which contains an area of high electron density.

Compare the properties between fuel and gasoline

Similarities:

* Both fractions are made up of alkanes 
* Both fractions consist of hydrocarbons 
* Fractions only contain single bonds/are saturated 

Differences:

* Fuel oil is less flammable
* Fuel oil is more viscous
* Fuel oil has a higher boiling point
* Fuel oil is a longer hydrocarbon

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(because fuel is near the bottom of the fractional column so it has longer chans)

Describe how you can test if a compound is (alkanes) saturated or (alkenes) unsaturated

* Add the compound that needs to be tested to a test tube
* using a pipette, add Br2 water to the sample
* if it stays orange then the compound is an alkane (saturated)
* if the solution turns from orange to colorless then its an alkene (unsaturated )

Product of incomplete combustion of hydro carbon

Releases carbon monoxide