Carbon Cycle & Fossils Fuels
The Carbon Cycle
The carbon cycle shows how carbon moves from the atmosphere, through animals and plants, then back into the atmosphere again.
All cells contain carbon compounds such as proteins, fats and carbohydrates. Carbon is passed from the atmosphere, as carbon dioxide, to living things. It is passed from one organism to the next in complex molecules, and returned to the atmosphere as carbon dioxide again.
The video below shows a brief description of the carbon cycle:-
In the atmosphere, carbon is attached to some oxygen in a gas called Carbon Dioxide.
Plants use Carbon Dioxide and the energy from sunlight to make their own food and grow. This is called Photosynthesis.
The Carbon becomes part of the plant. Plants that die and are buried may turn into fossil fuels made of carbon like Coal over millions of years.
When humans burn fossil fuels most of the carbon quickly enters the atmosphere as the gas Carbon Dioxide.
The carbon cycle shows where the carbon which you use comes from, and also where the carbon that you produce goes.
Many of the fuels we use in everyday life are obtained from fuels called fossil fuels. These fuels are mostly hydrocarbons – compounds that contain the elements carbon and hydrogen only but contain some impurities which can lead to pollution when we burn them.
Fossil fuels like coal, crude oil and natural gas have been formed over millions of years from dead plant and animal remains which have been buried under many layers sediment.
The video below shows how the process of sedimentation can be seen in the lab:-
The video below shows how "coal" in the form of Carbon can be formed from "plant materials" in the form of sugar:-
When a substance burns, it reacts with oxygen. This is known as combustion.
All combustion reactions are exothermic because they release energy, e.g. heat energy is given out when methane is burned in a Bunsen burner.
In order for combustion to happen, three things are needed:-
If any of the three are removed, the combustion will stop. This is how firefighters put out fires, by either:-
Removing the heat - for example, using water hoses to cool burning timber.
Removing the Oxygen - for example, using a Carbon Dioxide fire extinguisher on an electrical fire.
Removing the fuel - for example, firefighters cutting a firebreak to stop a forest fire.
Fire extinguishers can be very useful in an emergency, but they must be used correctly or they can make the situation worse!
The safest option if you discover a fire is to leave the area and call 999 immediately.
Each fire extinguisher is designed to work with a specific type of fire:-
Working as a Firefighter you would protect and save people and property from fire and other dangers. You’d respond to emergencies, and rescue people from life-threatening situations.
You’d also help to prevent fires by giving people advice about fire safety.You’d need to be able to react quickly and remain calm in dangerous situations. You’d inspire the public’s confidence in rapidly-changing situations. Self-discipline, teamwork and following safety regulations are crucial.
In the fire prevention side of the job you would give talks and presentations to schools and other community groups. You would also inspect buildings to make sure that they meet fire safety regulations. When new buildings are being constructed you’d advise on fire safety measures.
Full Time Firefighter
A Career in FIREFIGHTING
Salary: from £23,366 to £59,565 per year
Firefighter working hours: 42 hours a week, which includes day and night shifts to cover a 24-hour service. As a retained firefighter, you would usually be based in rural areas or smaller towns. You may have another job but you would make yourself available in emergency situations.
Typical entry requirements: Currently there are no set entry requirements for this role however this may change in the future.
It would be useful to have : English and Maths to National 5 Level. Also Skills for Work Uniformed and Emergency Services (SCQF level 4), SQA Leadership Award (SCQF level 5/6) can be beneficial.
Attention to detail
Combustion - Hydrocarbons
Crude oil is a mixture of hydrocarbons. Energy is released during burning/oxidation and respiration. The most common form of oxidation is the direct reaction of a fuel with oxygen through combustion. Combustion is the reaction of burning a fuel in oxygen. Burning natural gas means reacting with the Oxygen in the air. There will be products from the reaction, these products can be collected and identified.
Combustion can take two forms:
Complete combustion - where the fuel was burned in a plentiful supply of oxygen to produce carbon dioxide and water.
Incomplete combustion - where the hydrocarbons burn in a limited supply to produce carbon monoxide (a poisonous gas) and carbon.
Fossil fuels release carbon dioxide gas when they burn which adds to the greenhouse effect and increases global warming. Of the three fossil fuels, for a given amount of energy released, coal produces the most carbon dioxide and natural gas produces the least.
Coal and oil contain sulphur impurities. When these fuels burn, the sulphur burns too which releases sulphur dioxide (SO2) gas. Sulphur dioxide causes breathing problems for living creatures and contributes to acid rain:-
Use of catalytic converters to reduce carbon monoxide emissions. In engines, catalytic converters can be used to minimise the output of carbon monoxide. Reducing carbon emissions. Ways to reduce carbon dioxide emissions are explored (including methods of carbon capture). Impact on the environment of burning fossil fuels including the effect on the carbon cycle. Combustion of fossil fuels impacts on the environment and contributes to the carbon cycle.
Conservation of mass during combustion
No atoms are created or destroyed in a chemical reaction. Instead, they just join together in a different way than they were before the reaction, and form products.
The total mass stays the same during a chemical reaction. This is the law of conservation of mass.
Example 1 -
Burning methane in oxygen :
Methane + oxygen carbon dioxide + water
16g + 64g 44g + 36g
Total = 80g Total = 80g
The total mass of the reactants equal the sum of the mass of the products.
States of Matter
The kinetic particle theory explains the properties of the different states of matter. The particles in solids, liquids and gases have different amounts of energy. They are arranged differently and move in different ways:-
Extracting materials from Crude Oil
Hydrocarbons are chemical compounds that contain the elements carbon and hydrogen only. They are compounds that are obtained from the fossil fuel crude oil by a process called fractional distillation. When oil is removed from the earth it is found as a mixture of different sized liquid molecules.
Fractional distillation separates a mixture into a number of different parts, called fractions. A tall fractionating column is fitted above the mixture, with several condensers coming off at different heights. The column is hot at the bottom and cool at the top. Substances with high boiling points condense at the bottom and substances with lower boiling points condense on the way to the top:-
The video below shows how different materials can be separated, including by fractional distillation:-
Offshore Drilling Worker
As an Offshore Drilling Worker, you would work as part of a team that controls and operates the drills on offshore facilities such as oil or gas rigs or drilling platforms. As a driller, you would supervise the drilling team and control the rate of drilling. It’s a highly skilled and responsible job.
As an assistant driller it would be your job to coordinate the activities on the drill floor. For example, you would pass on instructions and information from the driller to the rest of the drilling team.
As a derrickman, you would work 20 to 25 metres above the rig floor on a platform attached to the derrick - the mast that supports the drilling equipment.
Offshore Drilling Worker
A Career as an offshore drilling worker
Salary: from £12,000 to £50,000 per year
Firefighter working hours: You would typically live and work on a rig or platform for two or three weeks, followed by two or three weeks’ rest period on shore. You would work up to 12 hours a day on a 24-hour shift rota.
Typical entry requirements: There are no formal qualifications required to enter this role but some employers may ask for qualifications at SCQF level 4/5 with a common route into the industry being through an apprenticeship scheme.
It would be useful to have : Maths, Science subjects, English and Technologies subjects such as engineering science to at least National 5 level.
Working with technology
Working with numbers
Attention to detail
Developing a plan