Lesson 4, Alkanes

• Scheikunde
• Middelbare school
• vwo
• Leerjaar 3

Complete this Mind Map

What do you know
about Hydrocarbons?

Alkanes and alkenes are both families of hydrocarbons.

Alkanes, or saturated hydrocarbons, contain only single covalent bonds between carbon atoms.

Alkenes have at least one double bond

Alkanes

The alkanes are a homologous series of hydrocarbons. This means that they have similar chemical properties to each other and they have trends in physical properties. For example, as the chain length increases, their boiling point increases.

The general formula of Alkanes

The general formula means that the number of hydrogen atoms in an alkane is double the number of carbon atoms (n), plus two.

If an alkane has 20 carbon atoms, how many hydrogen atoms will it have?

Is C10H22 an alkane?

Structural formula

Alkane molecules can be represented by displayed formulae in which each atom is shown as its symbol (C or H) and the covalent bonds between them by a straight line.

Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds. This makes them relatively unreactive, apart from their reaction with oxygen in the air - which we call burning or combustion.

Draw the structural formula of C4H10

Isomerism

Alkanes with more than 3 carbons can show constitutional isomerism. They can have either linear or branched structures (page 243). This is categorized as chain isomerism.

Find out the number of isomers of C4H10 and draw the structures of all of them.

Read page 242 and the first part (Structural formulas and isomerism) of page 243

Watch the first 2 minutes of the video, then go back to slide 9 and check your answer 

Classify each compound as organic or inorganic.

C6H10
CoCl2
C12H22O11

In the homologous series of alkanes, what is the molecular formula for the member just above C8H18? How did you work out the answer?

Use the general formula for alkanes to write the molecular formula of the alkane with 12 carbon atoms.

Write the condensed structural formula (Hint: page 243, just above part "Systematic naming)  for each structural formula.

Write the condensed structural formula (Hint: page 243, just above part "Systematic naming) for each structural formula.

Write the condensed structural formula (Hint: page 243, just above part "Systematic naming) for each structural formula.