Carbon based fuels revision

Renewable

Can be replaced (by natural resources) at the same rate or faster than consumed

non-renewable

Cannot be replaced (by natural processes) at the same rate or faster than consumed

sustainable

Able to meet the energy demands of society now and in the future

unsustainable

Cannot meet the energy demands of society now and in the future

fuel

A substance that contains stored chemical energy that can be released relatively easily

biofuel

a fuel derived from recently living organic matter.

Anaerobic

a process that occurs in the absence of oxygen

Bioethanol

Ethanol that is made by fermenting the sugar and starch components of plants using yeast.

Biogas

A mixture of gases (methane and carbon dioxide) produced by the breakdown of organic matter in the absence of oxygen.

Enhanced greenhouse gas effect

An increase in temperature of the Earth's surface due to an increased concentration of greenhouse gases in the atmosphere as a result of human activity

fossil fuel

A fuel that is produced from ancient plants, animals and microorganisms that have been buried under rock, mud and sand for millions of years.

Fractional distillation

the separation of components of a mixture based on their boiling points

Fracking

the process of injecting water, sand and chemicals at high pressure into coal or rock to fracture it and release trapped natural gas

liquefied petroleum gas (LPG)

Mixture of liquefied propane (C3H8) and butane (C4H10) gas removed from natural gas and used as a fuel.

carbon neutral

A process that absorbs the same amount of carbon dioxide as it generates.

Photosynthesis

the chemical process by which oxygen and glucose are produced in plant cells in the presence of UV light

combustion reaction

a chemical change in which an element or a fuel reacts with oxygen, often producing carbon dioxide, water and energy in the form of heat

System

the chemical reaction

surroundings

everything outside the system that can exchange energy and/or matter with the system

exothermic reaction

a chemical reaction that releases energy to its surroundings

endothermic reaction

a chemical reaction that absorbs energy from its surroundings

activation energy (Ea)

the minimum amount of energy required to break bonds in the reactants and initiate a chemical reaction

Complete combustion

A combustion reaction in which the only products are carbon dioxide and water

Incomplete combustion

The process by which a fuel burns insufficient oxygen to produce carbon monoxide (CO) and water as products

Examples of fossil fuels

• Coal

• Oil

• Natural gas

How are fossil fuels made

They are formed by the remains of ancient plants, animals and microorganisms that were buried under layers of mud, sand and rock.

What is the equation for photo synthesis

6CO2(g) + 6H2O(l) → C6H12O6(aq) + 6O2(g) catalysts : UV light and chlorophyll

what is the equation for a combustion reaction

Fuel + oxygen = carbon dioxide + water + energy

Bio diesel

A fuel derived from vegetable oil or animal fat, consisting of long-chain methyl esters.

Transesterfication

A process in which a triglyceride (fat and oil) reacts with a small alcohol (such as methanol), in the presence of a potassium hydroxide catalyst, to form an ester (biodiesel) 

What is another name for biodiesel

Fatty acid methyl ester (FAME)

Greenhouse gas

A gas that is able to absorb or re-radiate heat radiation.

3 main greenhouse gases

Methane, carbon dioxide and water vapour

Hygroscopic

The property of absorbing moister from the air

Feed stocks

Organic material from recently living things such as crops

Fermentation

The breakdown of sugar solutions, by the action of enzymes in yeasts, into ethanol and carbon dioxide

Equation for fermentation

C6H12O6(aq) → 2C2H5OH(aq) + 2CO2(g) (catalysts : yeast and enzymes)

Petrodiesel

The most common form of diesel fuel. It is produced from crude oil by fractional distillation.

E10

A petrol blend that contains no more than 10% ethanol

Catalyst

A substance that increases the rate of a reaction, but is not consumed in the reaction.

Equation for the production of biogas

Organic matter → ​CH4(g) ​+CO2​(g) (Catalyst : Anaerobic bacteria)

Explain nearly carbon neutral

• Plants absorb CO2 from the atmosphere during photosynthesis

• Similar amounts of CO2 are released into the atmosphere during combustion

• Additional CO2 is released during the farming, transportation and refining of the fuel

Why is black coal preferred

Black coal has a high carbon content (90%) and low water content (10%)

Crude oil

A mixture of hydrocarbon molecules : most are alkanes

Advantages of fossil fuels

• Reliable

• High energy content

• Abundant

• More efficient

Disdvantages of fossil fuels

• Not sustainable

• Non renewable

• Greenhouse gas emissions

3 main bioethanol feedstocks

Sugarcane, wheat and forest waste

Why does forest waste have to go through pre-treatment?

Forest waste contains a lot of cellulose which have strong hydrogen bonds. It would need to go through pre-treatment to break the bonds before turning it into glucose.