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Environmental Science - Blog Posts
“Those who dwell, as scientists or laymen, among the beauties and mysteries of the earth are never alone or weary of life. Whatever the vexations or concerns of their personal lives, their thoughts can find paths that lead to inner contentment and to renewed excitement in living. Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts.”
— Rachel Carson, The Sense of Wonder
New physics doesn’t always come from the recesses of space or the bowels of the Large Hadron Collider. Sometimes, you just need some cameras, a nickel bead, a magnet, and Petri dish popsicles.
Every once in a while, someone notices a big disc of ice eerily spinning in a river. These discs can be anywhere from 1 to 200 metres across, and almost everything about them has mystified physicists and environmental scientists for over a century. While it’s thought that this rare natural phenomenon is likely was caused by cold, dense air coming in contact with an eddy in a river, no one’s been able to definitively explain why these giant discs continue to rotate as they melt. Until now.
The most common explanation for the spinning ice discs says that as the discs float along in a river, they’re spun around by eddies - little spinning currents that form when water flows over rocks or into an enclosed space. And while this is this is probably part of what’s happening, it can’t be the whole story.
Combusting Alkanes
If you follow this blog, by now you must be thinking, when will we be done with the alkane chemistry? Well, the answer is never. There is still one more topic to touch on - burning alkanes and the environmental effects. Study up chums!
Alkanes are used as fuels due to how they can combust easily to release large amounts of heat energy. Combustion is essentially burning something in the presence of oxygen. There are two types of combustion: complete and incomplete.
Complete combustion occurs when there is a plentiful supply of air. When an alkane is burned in sufficient oxygen, it produces carbon dioxide and water. How much depends on what is being burnt. For example:
butane + oxygen -> carbon dioxide + water
2C4H10 (g) + 13O2 (g) -> 8CO2 (g) + 10H2O (g)
Remember state symbols in combustion reactions. In addition, this reaction can be halved to balance for 1 mole of butane by using fractions when dealing with the numbers.
C4H10 (g) + 6 ½ O2 (g) -> 4CO2 (g) + 5H2O (g)
Incomplete combustion on the other hand occurs when there is a limited supply of air. There are two kinds of incomplete combustion. The first type produces water and carbon monoxide.
butane + limited oxygen -> carbon monoxide + water
C4H10 (g) + 4 ½ O2 (g) -> 4CO (g) + 5H2O (g)
Carbon monoxide is dangerous because it is toxic and undetectable due to being smell-free and colourless. It reacts with haemoglobin in your blood to reduce their oxygen-carrying ability and can cause drowsiness, nausea, respiratory failure or death. Applicances therefore must be maintained to prevent the formation of the monoxide.
The other kind of incomplete combustion occurs in even less oxygen. It produces water and soot (carbon).
butane + very limited oxygen -> carbon + water
C4H10 (g) + 2 ½ O2 (g) -> 4C (g) + 5H2O (g)
Internal combustion engines work by changing chemical energy to kinetic energy, fuelled by the combustion of alkane fuels in oxygen. When this reaction is undergone, so do other unwanted side reactions due to the high pressure and temperature, e.g. the production of nitrogen oxides.
Nitrogen is regularly unreactive but when combined with oxygen, it produces NO and NO2 molecules:
nitrogen + oxygen -> nitrogen (II) oxide
N2 (g) + O2 (g) -> 2NO (g)
and
nitrogen + oxygen -> nitrogen (II) oxide
N2 (g) + 2O2 (g) -> 2NO2 (g)
Sulfur dioxide (SO2) is sometimes present in the exhaust mixture as impurities from crude oil. It is produced when sulfur reacts with oxygen. Nitrogen oxides, carbon dioxide, carbon monoxide, carbon particles, unburnt hydrocarbons, water vapour and sulfur dioxide are all produced in exhaust fumes and are also pollutants that cause problems you need to be aware of for the exam as well as how to get rid of them.
Greenhouse gases contribute to global warming, an important process where infrared radiation from the sun is prevented from escaping back into space by atmospheric gases. On the one hand, some greenhouse gases need to continue this so that the earth can sustain life as it traps heat, however, we do not want the earth’s temperature to increase that much. Global warming is the term given to the increasing average temperature of the earth, which has seen an increase in the last few years due to human activity - burning fossil fuels like alkanes has produced more gases which trap more heat. Examples of greenhouse gases include carbon dioxide, methane and water vapour.
Another pollution problem the earth faces is acid rain. Rain water is already slightly acidic due to the CO2 present in the atmosphere but acid rain is more acidic than this. Nitrogen oxides contribute to acid rain although sulfur dioxide is the main cause. The equation for sulfur dioxide reacting with water in the air to produce oxidised sulfurous acid and therefore sulphuric acid is:
SO2 (g) + H2O (g) + ½ O2 (g) -> H2SO4 (aq)
Acid rain is a problem because it destroys lakes, buildings and vegetation. It is also a global problem because it can fall far from the original source of the pollution.
Photochemical smog is formed from nitrogen oxides, sulfur dioxide and unburnt hydrocarbons that react with sunlight. It mostly forms in industralised cities and causes health problems such as emphysema.
So what can we do about the pollutants?
A good method of stopping pollution is preventing it in the first place, therefore cars have catalytic converters which reduce the amount of carbon monoxide, nitrogen oxides and unburnt hydrocarbons come into the atmosphere by converting them into less toxic gases. Shaped like a honeycomb for increased SA and therefore rate of conversion, platinum and rhodium coat ceramic and act as catalysts for the reactions that take place in an internal combustion engine.
As they pass over the catalyst, they react with each other to form less pollution:
octane + nitrogen (II) oxide -> carbon dioxide + nitrogen + water
C8H18 (g) + 25NO -> 8CO2 (g) + 12 ½ N2 (g) + 9H2O (g)
nitrogen (II) oxide + carbon monoxide -> carbon dioxide + nitrogen
2NO (g) + 2CO (g) -> 2CO2 (g) + N2 (g)
Finally, sulfur dioxide must be dealt with. The first way it is dealt with is by removing it from petrol before it can be burnt, however, this is often not economically favourable for fuels used in power stations. A process called flue gas desulfurisation is used instead.
In this, gases are passed through a wet semi-solid called a slurry that contains calcium oxide or calcium carbonate. These neutralise the acid, due to being bases, to form calcium sulfate which has little commercial value but can be oxidised to produce a more valuable construction material.
calcium oxide + sulfur dioxide -> calcium sulfite
CaO (s) + SO2 (g) -> CaSO3 (s)
calcium carbonate + sulfur dioxide -> calcium sulfite + carbon dioxide
CaCO3 (s) + SO2 (g) -> CaSO3 (s) + CO2 (g)
calcium sulfite + oxygen -> calcium sulfate
CaSO3 (s) + O -> CaSO4 (s)
SUMMARY
Alkanes are used as fuels due to how they can combust easily to release large amounts of heat energy. Combustion is essentially burning something in the presence of oxygen.
Complete combustion occurs when there is a plentiful supply of air. When an alkane is burned in sufficient oxygen, it produces carbon dioxide and water
Remember state symbols in combustion reactions. In addition, reactions can be halved to balance for 1 mole of compounds by using fractions when dealing with the numbers.
Incomplete combustion occurs when there is a limited supply of air. There are two kinds of incomplete combustion.
The first type produces water and carbon monoxide.
Carbon monoxide is dangerous because it is toxic and undetectable due to being smell-free and colourless. It reacts with haemoglobin in your blood to reduce their oxygen-carrying ability and can cause drowsiness, nausea, respiratory failure or death.
The other kind of incomplete combustion occurs in even less oxygen. It produces water and soot (carbon).
Internal combustion engines work by changing chemical energy to kinetic energy, fuelled by the combustion of alkane fuels in oxygen. When this reaction is undergone, so do other unwanted side reactions due to the high pressure and temperature, e.g. the production of nitrogen oxides.
Nitrogen is regularly unreactive but when combined with oxygen, it produces NO and NO2 molecules:
Sulfur dioxide (SO2) is sometimes present in the exhaust mixture as impurities from crude oil. It is produced when sulfur reacts with oxygen.
Nitrogen oxides, carbon dioxide, carbon monoxide, carbon particles, unburnt hydrocarbons, water vapour and sulfur dioxide are all produced in exhaust fumes and are also pollutants that cause problems you need to be aware of for the exam as well as how to get rid of them.
Greenhouse gases contribute to global warming, an important process where infrared radiation from the sun is prevented from escaping back into space by atmospheric gases. Some greenhouse gases need to continue this so that the earth can sustain life as it traps heat, however, we do not want the earth’s temperature to increase that much. Global warming is the term given to the increasing average temperature of the earth, which has seen an increase in the last few years due to human activity - burning fossil fuels like alkanes has produced more gases which trap more heat.
Another pollution problem the earth faces is acid rain. Nitrogen oxides contribute to acid rain although sulfur dioxide is the main cause.
Acid rain is a problem because it destroys lakes, buildings and vegetation. It is also a global problem because it can fall far from the original source of the pollution.
Photochemical smog is formed from nitrogen oxides, sulfur dioxide and unburnt hydrocarbons that react with sunlight. It mostly forms in industralised cities and causes health problems such as emphysema.
A good method of stopping pollution is preventing it in the first place, therefore cars have catalytic converters which reduce the amount of carbon monoxide, nitrogen oxides and unburnt hydrocarbons come into the atmosphere by converting them into less toxic gases. Shaped like a honeycomb for increased SA and therefore rate of conversion, platinum and rhodium coat ceramic and act as catalysts for the reactions that take place in an internal combustion engine.
As they pass over the catalyst, they react with each other to form less pollution.
octane + nitrogen (II) oxide -> carbon dioxide + nitrogen + water
C8H18 (g) + 25NO -> 8CO2 (g) + 12 ½ N2 (g) + 9H2O (g)
nitrogen (II) oxide + carbon monoxide -> carbon dioxide + nitrogen
2NO (g) + 2CO (g) -> 2CO2 (g) + N2 (g)
Finally, sulfur dioxide must be dealt with. The first way it is dealt with is by removing it from petrol before it can be burnt, however, this is often not economically favourable for fuels used in power stations. A process called flue gas desulfurisation is used instead.
In this, gases are passed through a wet semi-solid called a slurry that contains calcium oxide or calcium carbonate. Since they are bases, these neutralise the acid to form calcium sulfate which has little commercial value but can be oxidised to produce a more valuable construction material.
Happy studying!
Was exploring my new plant identification book. New name for the LGBT+ community just dropped:
Salmon are this timelines anchor being species
“And, while expressing gratitude seems innocent enough, it is a revolutionary idea. In a consumer society, contentment is a radical proposition. Recognizing abundance rather than scarcity undermines an economy that thrives by creating unmet desires. Gratitude cultivates an ethic of fullness, but the economy needs emptiness.” (111)
Braiding Sweetgrass by Robin Wall Kimmerer
“…the logic of knowledge as a network, adaptive and not commodified, is the most important beacon to orient ourselves and make sure the future exists. What can we learn from this knowledge? For me the greatest lesson is that quality is the most important and sustainable ting. A territory’s criterion of quality gathers together the ethics of that territory’s community, its notion of what is life, what is justice, what is abundance, and what is wellbeing” (66).
The Solutions Are Already Here by Peter Gelderloos
22nd April, 2025
The entire world comes together to celebrate our home. Mother Earth. This year, the theme for Earth Day is Our Power, Our Planet. This urges us to realise the importance of sustainable and renewable energy to build a healthy future for the coming generations.
Energy powers the world. From homes to industries to global economies. Historically, natural resources like wood and sunlight powered life on Earth. But after the Industrial Revolution, the dependence on fossil fuels like coal and petroleum has increased significantly. Today, as the field of technology gets more advanced, the energy demands have gone up, pushing us to explore much safer, sustainable options to meet our growing needs.
So what are our sustainable options?
Renewable Energy
Renewable Energy is derived from natural sources that replenish themselves. For instance, sunlight, potential energy from wind or flowing water. They’re sustainable, do not release any greenhouse gases upon being harnessed and decrease our dependence on fossil fuels. However, they come with their own set of challenges. Initial costs for infrastructure can be high, and some renewable sources, like solar and wind, can be intermittent, depending on weather conditions. Despite these challenges, investing in renewable energy is crucial for a cleaner, more sustainable future.
It is essential to switch to renewable energy for a sustainable future. It reduces our dependence on fossil fuels, enhancing geopolitical stability by decreasing energy-related conflicts. Moreover, renewable energy offers social and health benefits. Cleaner air, cleaner water, and cleaner soil lead to healthier communities. Investing in sustainable energy also drives innovations, creates jobs in multiple sectors, and promotes long-term growth of not just the environmental sector, but many other sectors too. And through this, we don’t just protect our planet but also build a stable and healthy society for future generations to come.
So this Earth Day, let’s come together and make our future sustainable.