Liquid fuel

Some liquids can make things move.

Most of these liquids come from deep in the ground. They are made from old plants and animals.

We use these liquids in cars and planes. They help us travel far away. It is the fumes that catch fire. This makes the liquid turn into power. These fuels are easy to move around. They are very helpful to us.

Liquid fuels are liquids that can make things move.

They provide power to help us travel. Most of these fuels come from petroleum. Petroleum forms from dead plants and animals deep in the Earth.

Gasoline is a very common liquid fuel. It is made from crude oil in refineries. When you use gasoline, the fumes catch fire. This makes the liquid turn into power. Gasoline has an octane rating. This number tells us how the fuel resists early burning. Higher numbers help fast race cars run better.

Diesel is another type of fuel. It is often cheaper to make than gasoline. Some diesel engines work by squeezing air. This heat helps the fuel burn.

Other fuels exist too. Ethanol is a type of alcohol. People often mix it with gasoline. There is also biodiesel. It is made from different sources than regular diesel. Some people use kerosene for lamps or small engines. Even natural gas can be turned into a liquid. This helps us move things around easily.

Liquid fuels are special liquids that create energy when they burn. They can be used to make machines move or create mechanical energy. These fuels always take the shape of the container they are in. Most of the liquid fuels we use today come from petroleum. Scientists believe petroleum formed from dead plants and animals long ago. These remains were buried under heat and pressure in the Earth's crust.

There are many different ways these fuels work. Gasoline is a very common fuel used in cars. It is made through a process called distillation in refineries. This process separates the useful liquid from crude oil. When you use gasoline, the liquid itself does not burn. Instead, the fumes from the liquid ignite and catch fire. This causes the liquid to evaporate and release its energy.

History shows us how different fuels have changed our lives. In the past, people used whale oil for light. Later, kerosene replaced it for lamps and cooking. In the mid-20th century, farmers used kerosene in tractors. They used a special heat valve to warm the fuel. This helped the engine switch from gasoline to kerosene. Chaim Weizmann also helped discover a way to make butanol in 1916. He used a bacterium to turn starch into useful chemicals.

Different fuels have unique facts and numbers. Gasoline has an octane rating to measure how it resists early burning. High-performance race cars need a higher octane rating to work well. Diesel is often cheaper to make than gasoline. In the United States, laws reduced sulfur in diesel from 3,000 ppm to 500 ppm in 2007. By 2010, that number dropped even lower to 15 ppm.

We can also find liquid fuels in other unexpected places. Ethanol is an alcohol found in many drinks. It is often mixed with gasoline to help the environment. Some people use a blend called E85, which is 85% ethanol. There is also biodiesel, which is similar to regular diesel. Even natural gas can be squeezed into a liquid state. This makes it much easier to move and use for power.

Liquid fuels are combustible molecules that generate energy. They can be harnessed to create mechanical energy, which usually results in kinetic energy. These fuels must also take the shape of their container. While the fluid itself is important, it is actually the fumes of liquid fuels that are flammable. Most liquid fuels used widely today are derived from fossil fuels. However, other types exist, such as hydrogen fuel, ethanol, and biodiesel. These fuels play a primary role in global transportation and the economy.

Liquid fuels possess several specific physical properties. These properties affect how safely the fuel can be handled. The flash point is the lowest temperature where a flammable concentration of vapor is produced. The fire point is the temperature where the burning of vapor becomes sustained. Diesel fuels also have a cloud point, which is the temperature where dissolved waxy compounds begin to coalesce. There is also a pour point, which is the temperature below which the fuel becomes too thick to pour freely. These properties vary by temperature, though not as much as they do for gaseous fuels.

Most current liquid fuels are produced from petroleum. Scientists believe petroleum formed from the fossilized remains of dead plants and animals. This happened through exposure to heat and pressure in the Earth's crust. Gasoline is the most widely used liquid fuel. It is made of hydrocarbon molecules, which are compounds containing only hydrogen and carbon. These form aliphatic compounds, which are chains of carbons with hydrogen atoms attached. Gasoline is produced through distillation of crude oil in refineries.

Gasoline is extremely volatile and can combust easily. When used, the liquid itself does not burn. Instead, its fumes ignite, causing the liquid to evaporate and then burn. Gasoline sold in many countries has an octane rating. This is an empirical measure of how much the fuel resists "knocking," or premature combustion. A higher octane rating allows for a higher compression ratio in engines. Engines with high compression ratios, like those in race cars, produce more power but require higher octane fuel. In the past, additives like tetra-ethyl lead were used to increase octane, but they are now being replaced due to environmental impacts.

Diesel is another major petroleum fuel. It is a mixture of aliphatic hydrocarbons. Diesel is generally cheaper to produce than gasoline because its extraction processes are simpler. In diesel engines, the fuel is ignited by being injected into a combustion chamber filled with compressed air. This compression raises the temperature to ignite the fuel. Producers often process diesel to reduce sulfur levels. High sulfur causes corrosion and acid rain. In the United States, the maximum sulfur content in diesel was reduced from 3,000 ppm in 2007 to just 15 ppm by 2010.

Kerosene is a versatile fuel used for lamps, cooking, and heating. It once displaced whale oil for lighting. Today, various grades of kerosene-type mixtures are used as jet fuel for jet engines. One form, known as RP-1, is burned with liquid oxygen as rocket fuel. In the mid-20th century, some tractors used a blend called tractor vaporising oil. These engines would start on gasoline and then switch to kerosene once warm. A heat valve would route exhaust gases to heat the kerosene so it could ignite with an electric spark.

Other liquid fuels come from non-petroleum sources. Biodiesel is similar to diesel but has a higher cetane rating, which is between 45 and 60. It can also act as a cleaning agent for deposits. Alcohols like ethanol and methanol are also used. Ethanol, or grain alcohol, is often blended with gasoline. A common blend is E85, which contains 85% ethanol and 15% gasoline. Another alcohol, butanol, can be produced by the bacterium Clostridium acetobutylicum. This process was first described by Chaim Weizmann in 1916.

Burning petroleum fuels releases carbon dioxide into the atmosphere. While carbon dioxide is necessary for plant growth, large-scale emissions can be harmful to the world climate. We can calculate how much is released by looking at the chemical makeup of the fuel. For example, burning 1 liter of diesel produces about 2.63 kg of carbon dioxide. This happens because the carbon in the fuel reacts with oxygen. Understanding these chemical processes helps scientists manage how we use energy and protect the environment.