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alkanes, halogenoalkanes - Coggle Diagram
alkanes
physical properties
POLARITY
- alkanes are almost non-polar, as the electronegativity between the carbon and hydrogen is similar
- only weak Van der Waal forces as intermolecular forces present (the larger the molecule the stronger the Van der Waal forces)
BOILING POINT
- the larger the hydrocarbon chain the higher the BP, due to increasing intermolecular forces
- branched chains have a lower MP than chains with the same number of carbons, this is because the branched chains cannot closely pack together so weak Van der Waal forces
SOLUBILITY - insoluble in water as hydrogen bonds present in water are stronger than Van der Waal forces
REACTIVITY
- very unreactive
- burn in the presence of oxygen
- react with halogens under suitable condition
COMBUSTION
Complete combustion
- shorter chain alkanes burn completely in plentiful supply of oxygen, producing CO2 and H2O
- release lots of heat energy and have a more negative enthalpy of combustion value
Incomplete combustion
- in limited supply of oxygen producing CO and H2O
- carbon soot is produced
polluting the atmosphere
- CO is a poisonous gas produced during incomplete combustion
- nitrogen oxides produced when there is enough energy for oxygen and nitrogen to react and combine (car engine), these cause acid rain
- sulfur dioxide contributes to acid rain, it is produced when sulfur reacts with water vapour producing acid rain
- CO2, greenhouse gas, increase in global temp
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- saturated hydrocarbons
- carbon and hydrogen atoms
- single bond
- used as fuels and lubricants
- CnH2n+2
halogenoalkanes
physical properties
POLARITY
- there is a higher difference in electronegativity between the carbon and halogen molecule
- down the group the bond becomes less polar
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