The Molecular Formulas Of Hydrocarbons

Submitted By cogfenwa
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Pages: 8

The molecular formulas of the hydrocarbons: Methane CH4 CH4
Ethane C2H6 CH3CH3
Propane C3H8 CH3CH2CH3
Butane C4H10 CH3CH2CH2CH3
Pentane C5H12 CH3CH2CH2CH2CH3
Heptane C6H14 CH3CH2CH2CH2CH2CH3
Hexane C7H16 CH3CH2CH2CH2CH2CH2CH3

Shapes - The shapes of the alkanes shows that all bonds on the carbon atoms are identical and that the bond angles are close to 109 degrees. Thus, each carbon atom is at the center of a tetrahedral structure, with either carbon atoms or hydrogen atoms at the apices of the tetrahedron. All bonds between carbon atoms (i.e. C-C bonds), or between a carbon atom and hydrogen (i.e. C-H bonds), are s bonds (sigma bonds). These bonds are formed by the end-on overlap of sp3 hydride orbitals of the carbon atoms.

Heat of combustion of the hydrocarbons : methane, ethane, propane, butane, pentane and hexane:

Heat of combustion of the alcohols: methane, ethane, propane, butane, pentane and hexane: The boiling points of the hydrocarbons: methane, ethane, propane, butane, pentane and hexane:

the advantages and disadvantages of the different fuels used in portable stoves: A gas cartridge is a mixture of two liquid petroleum gases (propane and butane) contained under pressure in a metal cartridge. They are used worldwide for their lightweight, portable nature, and the accuracy with which the flame produced can be adjusted.

How is it lit?

When the pressure in the cartridge is released by opening the stove valve the fuel emerges as a vapour. Lights instantly, without flaring. How long do the cartridges last?

Most stoves burn at around 150g/h (grams per hour). This is the rate at which the stove consumes fuel. This information will be found on either the packaging or the information booklet inside.

By doing a simple conversion i.e. a stove burns 150g/h, a gas cartridge has 450g of gas, you will be able to extract a rough estimate of how long the cartridge will last.

1 litre of water should take around 3-6 minutes to boil. This is longer in colder temperatures, but shorter at altitude as all gas cartridges work better as altitude increases and air pressure is lower. Heat output declines as cartridge empties and pressure drops. This can be counteracted by using fresh cartridges to bring liquids to the boil and quickly swapping with near-empty ones for simmering (re-sealable cartridges only).

Liquid Fuel
Why Liquid Fuel?
Ignites instantly. Unlike other fuels, it burns as a liquid not as a gas and so does not need to be pressurised. It is unaffected by temperature. Spilt fuel quickly evaporates, but until it has done so it will burn in both liquid and vapour form if ignited, so great care is needed when refilling.
Easily obtained worldwide.

What Liquid Fuels are available?
Methylated Spirits (Meths)

Meths is a form of ethanol (ethyl alcohol) that has been made unsuitable for drinking by the addition of about 9.5% of methanol (methyl alcohol), about 0.5% of pyridine, and a methyl violet dye (it is this dye that gives Meths its distinctive purple colour). Meths burns at half the heat of other fuels so twice as much is needed, leading to more bulk and weight in the rucksack.

Coleman fuel

Coleman fuel is a distilled form of petrol without the additives that can block fuel lines and jets causing stoves to flare and smoke. However it does need to be pressurised and burned as a vapour to ignite. Unleaded petrol This is the most widely used vehicle fuel in the UK, Europe and the USA. It is not as clean as Coleman fuel…