Alkanes

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Alkanes

• The Simplest Hydrocarbons

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Learning outcomes Define and recognise simple
alkanes. Write the correct chemical formula of
an alkane represented by a structural
formula. Given named examples, draw diagrams and
write the formulae of simple alkanes. Recall and
use the formula of an alkane, when n is given.
Keywords Hydrocarbon, alkane, saturated,
formula.
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What is the simplest compound that can be made
using one carbon atom and some hydrogen atoms?
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METHANE
The methane molecule is saturated
What would the formula for methane be?
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ETHANE
Formula?
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PROPANE BUTANE
Formula? Ball and stick diagram?
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Can you write a general formula for alkanes? If
number of carbon atoms is n then formula ?
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Extra info. Double (and triple) bonds are
possible. More H atoms could be added so this
molecule is NOT saturated This hydrocarbon
contains an oxygen atom also It is one of my
favourites The alkanes we have looked at are
linear. There are also branched alkanes and other
possibilities.
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• What is a hydrocarbon?
• What is an alkane?
• Pentane is an alkane with 5 carbon atoms. Draw a
  ball and stick model to show its structure and
  write its formula.
• What does a saturated molecule not contain?
• What is an important use for alkanes?

• 6. Here is an equation for the combustion of
  methane
• CH4 2O2 ? CO2 2H2O
• What are the reactants?
• What are the products?
• Is this equation balanced? Explain.