9.5.3 Petroleum

What it is: The name petroleum is derived from Latin words:

• **Petra** = rock
• **Oleum** = oil

It is also known as crude oil.

Key features:

• Petroleum or crude oil is a thick dark liquid composed mostly of hydrocarbons.
• Natural gas, usually associated with petroleum deposits, consists mostly of methane.
• It also contains significant amounts of ethane, propane, and butane.

How it is extracted:

• Petroleum is extracted by drilling holes into the earth's crust where it is found.
• When a drill is made through the rocks, natural gas comes out first with great pressure.
• After the gas pressure subsides, crude oil is extracted by pumps.

Key point: Petroleum is a liquid fossil fuel composed mostly of hydrocarbons. It is extracted by drilling.

Summary Table

Intermediate Level

Coal:

• Found in sedimentary rock deposits.
• Burned for fuel and electricity generation.
• Leading source of energy in the world.
• Non-renewable resource.

Natural Gas:

• Gaseous mixture of hydrocarbons.
• Main component: methane.
• Also contains ethane, propane, butane, CO₂, N₂, H₂S, and helium.
• Used for heating, electricity, and fuel for vehicles and spacecraft.

Petroleum:

• Also called crude oil.
• Thick dark liquid composed mostly of hydrocarbons.
• Associated natural gas consists mostly of methane and also contains ethane, propane, and butane.
• Extracted by drilling holes into the earth's crust.
• Natural gas comes out first, then crude oil is extracted by pumps.

Key point: Fossil fuels are non-renewable energy sources formed from ancient organisms. They include coal, natural gas, and petroleum.

Important Points

• - Fossil fuels = natural energy sources formed from the remains of ancient organisms.
• - They are non-renewable — once used, they cannot be replaced quickly.
• - The three main fossil fuels are:
• 1. Coal — solid; burned for fuel and electricity; leading source of energy.
• 2. Natural Gas — gas; main component is methane; used for heating, electricity, and fuel.
• 3. Petroleum — liquid; also called crude oil; a mixture of hydrocarbons; extracted by drilling.
• - Coal is found in sedimentary rock deposits.
• - Natural gas also contains ethane, propane, butane, CO₂, N₂, H₂S, and helium.
• - Petroleum is a thick dark liquid composed mostly of hydrocarbons.
• - Extraction of petroleum: Drilling holes into the earth's crust; natural gas comes out first, then crude oil is extracted by pumps.

Remember

• - Fossil fuels = natural energy sources from ancient organisms.
• - Non-renewable.
• - Three main fossil fuels: coal, natural gas, petroleum.
• - Coal = solid; leading source of energy.
• - Natural gas = gas; main component methane.
• - Petroleum = liquid; also called crude oil.
• - Petroleum is extracted by drilling.
• - Natural gas comes out first, then crude oil.

Common Mistakes

Quick Revision

Fossil Fuels:

Where does most of the energy used today come from?

Fossil fuels are natural energy sources. Fossil fuels are a non-renewable energy source. It is believed that they are formed from the remains of ancient organisms. They include coal, natural gas, and petroleum.

9.5.1 Coal: Coal is a material usually found in sedimentary rock deposits where rock and dead plant and animal matter are piled up in layers. It can be burned for fuel and used to generate electricity. Coal is the leading source of energy in the world. Because coal takes millions of years to develop and there is a limited amount of it, it is a non-renewable resource.

9.5.2 Natural Gas: Natural gas is a gaseous mixture of hydrocarbons that occurs naturally. The main component of natural gas is methane, but there are also small amounts of other high-alkanes such as ethane, propane, and butane, as well as trace gases such as carbon dioxide (CO₂), nitrogen (N₂), hydrogen sulfide (H₂S), and helium. Natural gas is used extensively for heating, electricity generation, and as a fuel for vehicles and spacecraft.

9.5.3 Petroleum: The name petroleum is derived from Latin words, petra meaning rock and oleum meaning oil. It is also known as crude oil. Petroleum or crude oil is a thick dark liquid composed mostly of hydrocarbons. Natural gas, usually associated with petroleum deposits, consists mostly of methane. It also contains significant amounts of ethane, propane, and butane.

Petroleum is extracted by drilling holes into the earth's crust where it is found. When a drill is made through the rocks, natural gas comes out first with great pressure. After the gas pressure subsides, crude oil is extracted by pumps.

60-Second Revision

• Fossil fuels = natural energy sources from ancient organisms.
• Non-renewable.
• Three main fossil fuels: coal, natural gas, petroleum.
• Coal = solid; leading source of energy.
• Natural gas = gas; main component methane.
• Petroleum = liquid; also called crude oil.
• Petroleum is extracted by drilling.
• Natural gas comes out first, then crude oil.
• Natural gas contains methane, ethane, propane, butane, CO₂, N₂, H₂S, helium.
• Petroleum is a thick dark liquid.
• ⚠️ Warning: fossil fuels are non-renewable — once used, they cannot be replaced quickly.