Obtaining and Using Hydrocarbons

Last Update: 19 November 2025

This is part of the HSC Chemistry course under the topic Hydrocarbons.

HSC Chemistry Syllabus

examine the environmental, economic and sociocultural implications of obtaining and using hydrocarbons from the Earth

How are Hydrocarbons Obtained from Earth?

Hydrocarbons, mainly alkanes, are extracted from crude oil/petroleum which forms in oil reservoirs within the lithosphere of Earth.

Geologists use seismic surveys to search for geological structures that may form oil reservoirs. One common method involves making an underground explosion nearby and observing the seismic response that provides information about the geological structures under the ground.

Extracting & Separating Hydrocarbons

Extracting crude oil normally starts with drilling wells into an underground reservoir.

The crude oil then undergoes fractional distillation, to separate the various components of the mixture into their useful fractions, based on their differences in boiling points which are mainly accounted by their differences in molecular weights and size (which determines dispersion force).

Larger hydrocarbons (higher boiling point) are condensed into liquid state first while those with lower boiling points remain in gaseous state and rise upwards in the distillation chamber. As the gaseous mixture rises, the temperature of the chamber continues to decrease. This allows components of the mixture with lower boiling points to condense sequentially.

Implications of Obtaining and Using Hydrocarbons From the Earth

The following list of implications is by no means exhaustive, but aims to act as a guide. Further research is encouraged especially for more personalised questions and depth studies.

Economic Implications

Positives

Significant economic growth for countries that have access to oil reservoirs as crude oil forms a major party of their export. The industry (exploration, extraction, refining, transport, distribution, and manufacturing of derived products) creates millions of jobs globally.
Hydrocarbons are currently the most energy-dense, affordable, and easily transportable fuels, making them essential for nearly all sectors. Their availability is key to energy security and maintaining global economic activity.

Hydrocarbons are the fundamental materials for the petrochemical industry, producing plastics, fertilisers, pharmaceuticals, synthetic fibers, and countless other materials that underpin the consumer economy.

Negatives

Global oil and gas prices are subject to geopolitical instability, supply shocks, and speculation. This volatility can cause rapid inflation, affect interest rates, and destabilise economies worldwide e.g. Ukraine-Russia crisis.
The economic costs of environmental damage (outlined below) are often not included in the market price of the fuel. As such, these impose a financial burden on society (healthcare costs, disaster relief, transition costs).

Sociocultural Implications

Positives

The cheap, abundant energy provided by hydrocarbons was a prerequisite for the invention and widespread use of cars, airplanes, heavy machinery, and the global shipping infrastructure, allowing for mass production, globalisation. It has also enabled systems that support modern life: heating, cooling, reliable lighting, and the complex agricultural system.
Chemical industries based around fossil fuels developed. These included manufactures of polymers, such as polyethylene, PVC and polystyrene, as well as synthetically produced materials including esters, acids, alcohols, nylon, polyesters, synthetic rubber. These chemicals, based on the petroleum industry, changed the lifestyles of society.

Negatives

Nations with large hydrocarbon reserves (like those in OPEC, Russia, and the US) gain significant political and economic leverage over energy-dependent consumer nations. Conversely, nations that lack domestic reserves are strategically vulnerable to supply disruptions, price manipulation, and political pressure from producer states. This drives foreign policy decisions and alliances.
Extraction projects (drilling, pipeline construction) often lead to the displacement of local communities, particularly Indigenous populations, and can result in the loss of traditional livelihoods and cultural sites.
Communities near extraction sites, refineries, or major transport routes often face disproportionately high levels of air and water pollution, leading to health crises and exacerbating social inequalities.

Environmental Implications

Extraction of crude oil from oil reservoirs creates large cavities underground which may cause overlying geological structures to collapse.
Oil spills impose significant damage to the environment especially aquatic ecosystems. Oils spills are also difficult to clean up.
Combustion of fuels releases greenhouse gases such as carbon dioxide. Methane a primary component of natural gas, can also inadvertently be released into the atmosphere during extraction, processing and combustion. The release of greenhouse gases leads to heat trapping and contribute to global warming.
Combustion of various fuel mixtures (containing sulfur, nitrogen) also releases pollutants such as sulfur oxides and nitrogen oxides. Both groups of oxides contribute to the formation of acid rain which has further downstream environmental consequences.

Table: Comparison of pollutants released from combustion of common fuels

Pollutant	Petrol	Diesel	Natural Gas
Particulate Matter	Lower (especially in modern engines)	Highest, consisting of fine soot and aerosols. This is a major public health concern.	Lowest
Nitrogen Oxides	Moderate (largely mitigated by catalytic converters)	High (formed under high-temperature combustion). A precursor to smog and acid rain.	Moderate/Low (can be higher in untreated exhaust)
Sulfur Dioxide	Low	High (due to higher sulfur content, though modern low-sulfur diesel has reduced this). Contributes to acid rain.	Very Low
Carbon Monoxide	High (especially when combustion is incomplete/idling)	Lower (due to leaner-burn engines)	High (especially in untreated exhaust from CNG vehicles)
Uncombusted Hydrocarbons	High (especially at startup/idling)	Low	High (primarily unburned methane, which is a GHG)

Materials produced by the chemical industry using components of crude oil as the raw materials are non-biodegradable. Therefore, their disposal poses an environmental concern, particularly in the long-term as the amount of non-biodegradable materials being used accumulate