Crude oils, Fuels and Organic Chemistry

• What is crude oil made from and how was it formed?

  Crude oil is a complex mixture of hydrocarbons formed over millions of years from the remains of simple marine organisms buried under sediment and exposed to heat and pressure.
• What is fractional distillation and how does it work?

  Fractional distillation separates crude oil into fractions based on boiling points. The oil is heated, vapours rise in the column and condense at different levels.
• What do fractions from crude oil contain?

  Fractions contain mixtures of hydrocarbons, mainly alkanes, with similar boiling points and chain lengths.
• How do boiling point, viscosity, and flammability change with hydrocarbon chain length?

  As chain length increases: boiling point increases, viscosity increases, and flammability decreases.
• Why is the oil industry globally important?

  It is vital for transport, energy, and industry. It affects economies, geopolitics, and has significant environmental and social impacts.
• What are the products of complete combustion of hydrocarbons?

  Carbon dioxide (CO₂) and water (H₂O).
• What are the products of incomplete combustion of hydrocarbons?

  Carbon monoxide (CO), carbon (soot), water (H₂O), and less energy.
• How can you measure the energy released per gram of fuel?

  Burn the fuel under a known mass of water, measure temperature change, and use: Energy (J) = mass of water × 4.2 × ΔT, then divide by grams of fuel burned.
• What is the combustion reaction for hydrogen?

  2H₂ + O₂ → 2H₂O
• What are the advantages and disadvantages of hydrogen as a fuel?

  Advantages: only water as product, renewable. Disadvantages: storage issues, production requires energy.
• What are the three elements of the fire triangle?

  Fuel, heat, and oxygen.
• What is cracking and why is it done?

  Cracking breaks long-chain alkanes into shorter alkanes and alkenes to make more useful products like fuels and monomers for plastics.
• What is the general formula for alkanes?

  CₙH₂ₙ₊₂
• What is the general formula for alkenes?

  CₙH₂ₙ
• Name and give formulae for the first 4 alkanes.

  Methane (CH₄), Ethane (C₂H₆), Propane (C₃H₈), Butane (C₄H₁₀)
• Name and give formulae for the first 3 alkenes.

  Ethene (C₂H₄), Propene (C₃H₆), Butene (C₄H₈)
• What is isomerism in hydrocarbons?

  Isomers have the same molecular formula but different structural formulae.
• How are more complex alkanes and alkenes named?

  By identifying the longest chain, locating branches or double bonds, and using prefixes/numbers.
• What happens when an alkene reacts with hydrogen?

  It undergoes addition to form an alkane.
• What happens when an alkene reacts with bromine water?

  An addition reaction occurs, and the orange bromine water becomes colourless.
• What is addition polymerisation?

  A reaction where many monomers (like alkenes) join to form a long-chain polymer.
• Name four common polymers made from alkenes.

  Polythene, Poly(propene), Poly(vinylchloride), and PTFE (Teflon).
• What are the properties and uses of polythene?

  Flexible and waterproof; used in bags and bottles.
• What are the properties and uses of poly(propene)?

  Tough and lightweight; used in containers and ropes.
• What are the properties and uses of poly(vinylchloride)?

  Rigid or flexible; used in pipes and electrical insulation.
• What are the properties and uses of PTFE (Teflon)?

  Non-stick and heat-resistant; used in non-stick pans and coatings.
• What are the environmental issues with plastic disposal?

  They are non-biodegradable, fill landfills, and contribute to pollution.
• How does recycling help with plastic waste and crude oil use?

  Reduces landfill, pollution, and conserves crude oil by reusing materials.
• How is ethanol made by fermentation?

  By using yeast to convert sugars into ethanol and carbon dioxide anaerobically.
• What is used to test for alcohols?

  Acidified potassium dichromate(VI), which turns from orange to green when oxidising alcohols.
• What are the social and economic impacts of alcoholic drinks?

  Health issues and addiction (social), and tax revenue and employment (economic).
• What are the uses of ethanol as a fuel and solvent?

  Used as a solvent in perfumes and as a renewable fuel (bioethanol).
• What factors affect the development of bioethanol fuel?

  Environmental (carbon-neutral), social (food vs fuel), and economic (production costs).
• Name and give formulae for simple alcohols.

  Methanol (CH₃OH), Ethanol (C₂H₅OH), Propanol (C₃H₇OH), including isomers.
• What is the product of microbial oxidation of ethanol?

  Ethanoic acid (CH₃COOH), a carboxylic acid.
• How can infrared spectroscopy identify organic compounds?

  By detecting characteristic bonds: C-H (alkanes), C=C (alkenes), O-H (alcohols), and C=O/O-H (carboxylic acids).