- Molecules in the alkane family are hydrocarbons.
- Consisting only of hydrogen and carbon.
- Atoms with alkane molecules are joined together with single bonds.
- This means the molecules are saturated.
- Methane- simplest hydrocarbon molecule and the smallest of the alkane family: 1 carbon atom, 4 hydrogen atoms
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The Alkanes Cont.
- Imagine the alkane molecules as being part of a family- next molecule in the series has a longer chain.
- Each time one more carbon atom is added and two more hydrogen.
- After methane comes ethane: C2H6.
- Methane, ethane, propane, butane, pentane, hexane, heptane,octane, nonane, decane...
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- Alkanes are used as fuels: they burn in air & release C02 and H2O.
- As chain length increases so does the boiling point.
- Alkanes do not react with aqueous substances: C-C & C-H bonds are unreactive.
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- Also organic molecules- but not hydrocarbons: oxygen is present.
- The hydroxy group gives alcohols its' characteristics: -OH.
- This is the functional group in an organic molecule.
- Methanol is the simplest alcohol
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- After methanol comes ethanol: C2H5OH.
- Alcohols burn in air = CO2 and H2O
- They are combustible because of the hydrocarbon in the chain.
- Alochol reacts with sodium less vigorously than sodium with water.
- Sodium replaces the hydrogen in the hydroxy group of the molecule.
- The products of the reaction are sodium ethoxide and hydrogen gas.
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