9.2 Hydrocarbons

• Hydrocarbons are used as fuels such as natural gas, petrol, and diesel.
• What is the composition of hydrocarbons?

  Carbon and hydrogen
• Alkanes have the general formula C_n H_{2n+2}.


  True
• What is the general formula for alkenes?

  $C_{n} H_{2n}$
• Hydrocarbons are compounds that contain only carbon and hydrogen atoms
• Hydrocarbons are used as fuels such as natural gas, petrol, and diesel.


  True
• Hydrocarbons release a lot of energy when burned due to their flammability.

  True
• Order the physical properties of alkanes as the number of carbon atoms increases:

  1️⃣ Boiling Point

  2️⃣ Melting Point

  3️⃣ Density

  4️⃣ Flammability
• Larger alkanes have higher boiling points than smaller alkanes.


  True
• Alkanes are a class of hydrocarbons with the general formula C_n H_2n+2
• The boiling point of alkanes increases as their size increases.


  True
• Match the property with the correct hydrocarbon type:

  Reactivity ↔️ Alkenes are more reactive

  Boiling Point ↔️ Alkanes have higher boiling points

  Flammability ↔️ Both alkanes and alkenes are flammable
• Alkenes are more reactive than alkanes because of their double bond
• Alkynes are hydrocarbons with a triple bond between two carbon atoms
• Alkenes are more reactive than alkanes because they can undergo addition
• What is the general formula for alkynes?

  $C_{n} H_{2n - 2}$
• Alkynes have lower boiling points than alkanes due to weaker intermolecular forces.


  True
• Alkanes belong to a homologous series because they have the same general formula
• Alkenes can undergo addition reactions due to their double bond.


  True
• What type of bond is present in alkenes that gives them different properties compared to alkanes?

  Double bond
• Larger alkanes have higher boiling points than larger alkenes.

  True
• Alkynes have a triple bond between two carbon atoms.
• What two elements do hydrocarbons contain?

  Carbon and hydrogen
• Hydrocarbons release a lot of energy when burned.


  True
• Hydrocarbons range from gases like methane to liquids like petrol.
• Alkenes are more reactive than alkanes and can undergo addition reactions.
• What type of bond is present in alkynes that makes them highly reactive?

  Triple bond
• The double bond in alkenes makes them more reactive and allows them to undergo addition reactions.
• Alkynes have higher boiling points than alkanes.

  False
• The triple bond in alkynes makes them highly reactive.
• Incomplete combustion occurs when there is sufficient oxygen available.

  False
• What type of byproduct is formed during substitution reactions?

  Hydrogen
• What prefix is used for a carbon chain with three carbon atoms?

  Prop-
• IUPAC stands for the International Union of Pure and Applied Chemistry
• The IUPAC naming rule for alkanes is to combine the parent chain name with the name of any substituents
• What is the first step in naming hydrocarbons using IUPAC rules?

  Identify the parent chain
• When naming alkenes, it is necessary to indicate the position of the double bond
• What is the composition of hydrocarbons?

  Carbon and hydrogen
• Hydrocarbons release a lot of energy when burned due to their high flammability.


  True
• Larger alkanes have higher boiling points