Question 1: Alkanes are saturated hydrocarbons with only single bonds between carbon atoms. Their general molecular formula is CₙH₂ₙ+₂. Explain what is meant by the term 'saturated hydrocarbon'.

Answer: A saturated hydrocarbon is a hydrocarbon where all carbon-carbon bonds are single bonds, with no double or triple bonds, meaning it has the maximum number of hydrogen atoms attached to the carbon chain.

Question 2: Calculate the molecular formula of an alkane with 4 carbon atoms.

Answer: C4H10

Question 1: Describe the typical physical state of alkanes with up to 4 carbon atoms at room temperature.

Answer: They are gases at room temperature.

Question 2: Write the balanced equation for the complete combustion of methane (CH₄).

Answer: CH₄ + 2O₂ → CO₂ + 2H₂O

Question 3: Multiple Choice: Which of the following is a primary use of alkanes?

Answer: As a fuel for heating and cooking

Question 1: Explain the mechanism of free radical substitution in alkanes during halogenation.

Answer: Free radical substitution of alkanes involves three steps: initiation, where radicals are generated; propagation, where radicals react with molecules to form new radicals and products; and termination, where radicals combine to form stable molecules, resulting in halogenated alkanes.

Question 2: Identify two safety precautions that should be taken when conducting experiments involving alkanes.

Answer: Use of safety goggles and working in a well-ventilated area to prevent inhalation of fumes and reduce fire risk.

Question 3: State one reason why alkanes are considered less reactive than alkenes.

Answer: Because alkanes have only single bonds, which are less reactive than the double bonds in alkenes.

Question 1: A refinery produces a mixture of alkanes mainly consisting of hexane (C₆H₁4) and octane (C₈H₁8). If the octane content increases, what effect does this have on the fuel's knocking characteristics?

Answer: An increase in octane improves the fuel's knocking resistance, making it more suitable for use in engines.

Question 2: Describe one environmental concern associated with the combustion of alkanes derived from crude oil.

Answer: The release of carbon dioxide (CO₂), which contributes to global warming.

Question 3: Identify a modern technological development that utilises alkanes or their derivatives.

Answer: The development of liquefied petroleum gas (LPG) for renewable energy sources.