What are the different types of fuels studied in IB MYP Organic Chemistry?

In the IB MYP Organic Chemistry curriculum, students study various types of fuels, including fossil fuels like coal, oil, and natural gas, as well as renewable fuels such as biofuels. These fuels are categorized based on their origin and environmental impact, with fossil fuels being non-renewable and contributing to greenhouse gas emissions, while biofuels are derived from biological materials and considered more sustainable.

How do fossil fuels impact the environment?

Fossil fuels, such as coal, oil, and natural gas, significantly impact the environment by releasing carbon dioxide and other greenhouse gases when burned. This contributes to global warming and climate change. Additionally, the extraction and transportation of fossil fuels can lead to habitat destruction, oil spills, and air and water pollution, making it a critical topic in the IB MYP Science curriculum.

What are biofuels and how are they different from fossil fuels?

Biofuels are renewable energy sources made from organic materials such as plants and animal waste. Unlike fossil fuels, which are finite and take millions of years to form, biofuels can be replenished relatively quickly. They are considered more environmentally friendly because they produce fewer greenhouse gases and can help reduce dependency on fossil fuels, a key point of study in IB MYP Organic Chemistry.

Why is the study of fuels important in the IB MYP Science curriculum?

Studying fuels in the IB MYP Science curriculum is important because it helps students understand the chemical processes involved in energy production and the environmental and economic implications of different fuel types. This knowledge is crucial for making informed decisions about energy use and sustainability, aligning with the program's goal of developing globally aware and responsible citizens.

What is the role of combustion in the use of fuels?

Combustion is a chemical process that occurs when a fuel reacts with oxygen to release energy in the form of heat and light. This process is fundamental to the use of fuels, as it powers engines, generates electricity, and provides heat. In the IB MYP Organic Chemistry curriculum, students explore the combustion reactions of different fuels, understanding both the energy output and the environmental impact of the byproducts, such as carbon dioxide and water vapor.

Why is "Treating petrol as the 'best' fuel." a common mistake in Fuels?

Why it happens: It's most familiar. How to avoid it: Petrol is GOOD for cars under current technology — but produces CO₂, depletes finite reserves, and adds air pollutants. Other fuels (gas, hydrogen, electricity) each have their own use cases.

Why is "Calling bioethanol 'zero emission' at the tailpipe." a common mistake in Fuels?

Why it happens: Carbon-neutral language is confusing. How to avoid it: Bioethanol DOES emit CO₂ at the tailpipe. The 'carbon-neutral' claim is about the LIFECYCLE — the CO₂ released was earlier absorbed by the crop. The total atmospheric CO₂ doesn't go up over a full cycle (in principle).

Organic chemistryIB MYP Sciences (Years 1-5)

Fuels

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Fuels — IB MYP Sciences: crude oil, fractional distillation, and choosing the right fuel

Most of the world's energy still comes from burning fuels. This MYP Sciences note covers what makes something a useful fuel, how crude oil is separated by fractional distillation, the comparison of fossil fuels with biofuels, and the climate problem at the heart of it all.

What you’ll learn

Mapped to the IB MYP Sciences subject guide (2026 onwards).

MYP Sciences A — Define a fuel and list properties of a 'good' fuel.
MYP Sciences A — Describe fractional distillation of crude oil.
MYP Sciences A — Name the main fractions and their uses.
MYP Sciences D — Evaluate fossil fuels vs biofuels vs hydrogen as energy carriers.

Fractional distillation of crude oil

Crude oil heated; vapour rises; different fractions condense at different heights.

Crude oil (also called petroleum) is a thick, dark, complex mixture of hydrocarbons. Refining splits it into useful fractions using fractional distillation.

How it works:

Crude oil is heated in a furnace to about 350-400 °C — most of it vaporises.
Vapour rises up a tall column (the fractionating column).
The column is HOT at the bottom and COOLER at the top.
As vapour rises, it gradually cools. Each fraction condenses out at a specific height where the temperature matches its boiling point range.

Main fractions, from top of column (lowest BP) to bottom (highest BP):

Fraction	Carbon range	Typical use
Refinery gas	C1-C4	Heating, cooking gas (LPG)
Petrol (gasoline)	C5-C10	Car engines
Naphtha	C7-C14	Petrochemical feedstock
Kerosene	C10-C16	Jet fuel, lamp oil, heating
Diesel (gas oil)	C12-C20	Diesel engines, trucks, trains
Fuel oil	C20-C40	Ship fuel, factory heating
Bitumen (residue)	C40+	Road surfaces, roofing

Properties shift gradually with chain length:

Longer chains → higher BP, more viscous (thick), less volatile, less flammable, darker colour.
Shorter chains → lower BP, runny, very volatile, easy to ignite.

This is why petrol is a runny liquid that ignites easily (so engines start cold) but bitumen is a thick black tar.

Crude oil = complex mixture of hydrocarbons.
Fractional distillation separates by boiling point.
Top of column: short chains (refinery gas, petrol). Bottom: long chains (bitumen).
Properties (BP, viscosity, volatility) change predictably with chain length.

What makes a good fuel?

Energy density, storability, clean burning, affordability.

Engineers and economists judge fuels on several criteria:

1. Energy density — how much energy per kg or per litre. Higher = better for transport (less mass to carry).

Petrol: ~46 MJ/kg.
Diesel: ~45 MJ/kg.
Hydrogen: ~120 MJ/kg (best by mass) but bulky to store.
Wood: ~15 MJ/kg.

2. Storage and transport — does it need refrigeration or compression? Is it stable at room temp?

Petrol: liquid at room T, easy to store.
Natural gas: needs pressurised tanks or LNG cooling.
Hydrogen: needs cryogenic or very-high-pressure storage.

3. Burns cleanly — minimum CO, soot, sulfur compounds.

Natural gas burns cleanest of fossil fuels.
Coal is dirtiest (often contains S and produces lots of CO₂ + particulates).
Hydrogen burns to just water → cleanest of all (at point of use).

4. Availability and price — is it abundant locally?

Saudi Arabia: oil is cheap and plentiful.
New Zealand: hydropower is local and cheap; oil is imported.
Choice often comes down to what's locally cheap.

5. Environmental impact — CO₂ per unit energy, other pollutants, land/water impact.

No fuel is perfect on all five criteria. Choosing a fuel is a TRADE-OFF.

Five criteria: energy density, storage, cleanliness, availability, environment.
No fuel is best on all five — always a trade-off.
Hydrogen burns cleanest but is hardest to store.

Fossil fuels, biofuels and hydrogen

Three families of fuel, three different climate profiles.

Fossil fuels (coal, oil, gas):

Formed over millions of years from ancient organisms.
Used in industry, transport, electricity.
FINITE — they will eventually run out.
Each kg burned releases CO₂ that was locked away millions of years ago → adds to atmospheric CO₂ → climate change.

Biofuels (ethanol, biodiesel, biogas):

Made from recent plant material (crops, algae, food waste).
RENEWABLE — crops regrow each year.
CARBON-NEUTRAL in principle: the CO₂ released was absorbed by the plant THIS year, not millions of years ago.
Drawback: growing fuel crops competes with food production.

Hydrogen (H₂):

Burns to water only (no CO₂ at point of use).
Has to be MADE from something else (electrolysis of water, or steam reforming of methane).
Greenness depends on the production route. 'Green' H₂ (renewable electricity → electrolysis) is genuinely zero-carbon. 'Grey' H₂ (from methane) still emits CO₂ during production.

Fuel	CO₂ at use	Renewable?	Storage
Petrol	Yes	No	Easy (liquid)
Bioethanol	Yes (but recycled)	Yes	Easy (liquid)
Hydrogen (green)	None	Yes	Hard (compressed/cryogenic)

MYP criterion D classic: 'Compare petrol, bioethanol and hydrogen as transport fuels.' Strong answers cover all three on at least: CO₂ profile, energy density, storage, infrastructure availability, and cost.

Fossil: finite, CO₂-emitting, easy to use.
Biofuels: renewable, near-carbon-neutral, but compete with food.
Hydrogen: zero CO₂ at use, but hard to store and depends on the production route for being truly green.

How it’s examined

Criterion A tests fractions and their uses. Criterion D often asks for a fuel comparison and an evaluation of environmental impact.

Sources: IB MYP Sciences guide (IBO, official subject guide). Last reviewed 2026-05-25.

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Step-by-step worked examples — Fuels

Step-by-step solutions to past-paper-style questions on fuels, written exactly the way a tutor would explain them at the board.

1Ordering the fractions
Getting started• fractions
Question
Order these fractions from lowest BP (top of column) to highest BP (bottom): diesel, petrol, bitumen, refinery gas.
Step-by-step solution
1. Step 1
  Refinery gas (~C1-C4) — shortest, lowest BP.
2. Step 2
  Petrol (~C5-C10).
3. Step 3
  Diesel (~C12-C20).
4. Step 4
  Bitumen (C40+) — longest, highest BP.
Answer
Refinery gas < petrol < diesel < bitumen.
2Choosing a fuel
Building confidence• properties
Question
Why is petrol preferred over coal for car engines?
Step-by-step solution
1. Step 1
  Petrol is a LIQUID — easy to pump, easy to meter precisely, easy to store in tanks.
2. Step 2
  Petrol has HIGHER ENERGY DENSITY (per kg) than coal.
3. Step 3
  Petrol burns CLEANER than coal (less soot, no S compounds).
4. Step 4
  Petrol fits internal-combustion engine design (vaporises easily, mixes with air).
Answer
Petrol is liquid (easy to handle), more energy-dense than coal, burns cleaner, and matches engine design.
3Three transport fuels
Stretch• evaluation
Question
Compare petrol, bioethanol and hydrogen for transport: tailpipe emissions, renewability and storage.
Step-by-step solution
1. Step 1
  Petrol: CO₂ at tailpipe; NOT renewable; liquid storage easy.
2. Step 2
  Bioethanol: CO₂ at tailpipe (but recycled from atmosphere by crops); renewable; liquid storage easy.
3. Step 3
  Hydrogen: just water at tailpipe; renewable IF green H₂; storage is HARD (high pressure or cryogenic).
Answer
Petrol: CO₂ + non-renewable, easy storage. Bioethanol: net-neutral CO₂ + renewable, easy storage. Hydrogen: zero CO₂ at use, renewable only if green, storage difficult.

Key Definitions and Keywords — Fuels

Definitions to memorise and the exact keywords mark schemes credit for fuels answers — sharpened from recent examiner reports for the 2026 IB MYP Sciences sitting.

Fuel
Examiner keyword
A substance that is burned to release useful energy.
Crude oil (petroleum)
Examiner keyword
A naturally-occurring complex mixture of hydrocarbons; the source of most fossil fuels.
Fractional distillation (of crude oil)
Examiner keyword
Industrial process that separates crude oil into useful fractions by boiling-point range in a tall column.
Fraction (of crude oil)
A group of hydrocarbons with similar chain lengths and BP range, collected together at one level of the column.
Biofuel
Examiner keyword
A fuel made from recently-grown organic material (e.g. bioethanol from crops, biodiesel from oilseeds). Considered renewable and near carbon-neutral.

Common Mistakes and Misconceptions — Fuels

The traps other students keep falling into on fuels questions — taken from recent IB MYP Sciences examiner reports and mark schemes — and how to avoid them.

✕Treating petrol as the 'best' fuel.
Why it happens
It's most familiar.
How to avoid it
Petrol is GOOD for cars under current technology — but produces CO₂, depletes finite reserves, and adds air pollutants. Other fuels (gas, hydrogen, electricity) each have their own use cases.
✕Calling bioethanol 'zero emission' at the tailpipe.
Why it happens
Carbon-neutral language is confusing.
How to avoid it
Bioethanol DOES emit CO₂ at the tailpipe. The 'carbon-neutral' claim is about the LIFECYCLE — the CO₂ released was earlier absorbed by the crop. The total atmospheric CO₂ doesn't go up over a full cycle (in principle).

Practice questions

Exam-style questions with step-by-step worked solutions. Try one before checking the method.

Past paper style quiz

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Fuels — frequently asked questions

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Fuels

Short Study Notes in the form of Slides

Short Study Notes — Fuels

Detailed Notes

What you’ll learn

How it’s examined

1Ordering the fractions

2Choosing a fuel

3Three transport fuels

Fuel

Crude oil (petroleum)

Fractional distillation (of crude oil)

Fraction (of crude oil)

Biofuel

✕Treating petrol as the 'best' fuel.

✕Calling bioethanol 'zero emission' at the tailpipe.

Practice questions

Past paper style quiz

Assess your understanding

Fuels — frequently asked questions