8. What are fossil fuels? Name main fossil fuel.

Fossil fuels are natural resources formed from the remains of ancient plants and animals that have undergone geological processes such as heat and pressure over millions of years. These fuels are rich in carbon and are combustible, making them valuable sources of energy for various human activities. The combustion of fossil fuels releases energy in the form of heat, which can be harnessed for electricity generation, transportation, heating, and industrial processes.

The main fossil fuels are:

1. Coal: Coal is a combustible sedimentary rock composed primarily of carbon, along with varying amounts of other elements such as hydrogen, sulfur, oxygen, and nitrogen. It is formed from the remains of terrestrial plants that lived millions of years ago in swampy environments. Coal is the most abundant fossil fuel and is used primarily for electricity generation, steel production, and heating.

2. Petroleum (Crude Oil): Petroleum, commonly known as crude oil, is a naturally occurring liquid mixture of hydrocarbons found in underground reservoirs. It is formed from the remains of marine organisms such as algae and plankton that were buried and subjected to heat and pressure over millions of years. Petroleum is refined into various products such as gasoline, diesel, jet fuel, lubricants, and petrochemicals, which are used in transportation, industry, agriculture, and manufacturing.

3. Natural Gas: Natural gas is a mixture of hydrocarbon gases, primarily methane (CH4), along with smaller amounts of ethane, propane, butane, and other gases. It is formed alongside petroleum deposits and can also be found in coal seams and shale formations. Natural gas is used for electricity generation, heating, cooking, and as a feedstock for the production of chemicals and fertilizers.

These fossil fuels are major contributors to global energy consumption and play crucial roles in powering economies, industries, and transportation systems worldwide. However, their combustion releases carbon dioxide and other greenhouse gases into the atmosphere, contributing to climate change and environmental degradation. As such, there is growing interest in transitioning to renewable energy sources and improving energy efficiency to reduce reliance on fossil fuels and mitigate their environmental impacts.