Acidic Oxides
Sulphur dioxide is a colourless, toxic gas, with a pungent odour and is soluble in water. It is extremely irritating to the eyes and respiratory tract, causing lung damage and asthma. Sulphur dioxide occurs naturally in the atmosphere through combustion of organic matter, decomposition of organic matter and volcanoes: S(s) + O2(g) → SO2(g). Industrial sources include combustion of fuels, metal smelters extracting zinc, copper and lead from sulfides
PbS + O2(g) → Pb(s) + SO2(g), incineration of garbage, petroleum refineries and use of sulphur dioxide in industries to produce sulfuric acid, paper, food processing and sewage treatment.
There are a number of oxides of nitrogen and they are represented as NOx, which refers to the NO and NO2 gases in the atmosphere. Nitrogen dioxide is a red-brown gas and is poisonous which makes it harmful to the respiratory system, causing decreased lung function, susceptibility to respiratory infections and increased sensitivity to asthma triggers. Nitrogen dioxide is an acidic oxide. A natural source is the action of sunlight on NO and O2. An industrial source is the combustion of fuel in motor vehicles and power stations. Dinitrogen monoxide is a colourless gas and it is neutral. A natural source of dinitrogen monoxide is produced by soil bacteria. Industrial sources of dinitrogen monoxide are manufactured as a fuel for racing cars and for use as a sedative. Nitrogen monoxide is a colourless gas and it is neutral. A natural source is produced by soil bacteria and lighting
N2(g) + O2(g) → 2NO(g). Industrial sources are produced by the burning of biomass and the combustion of fuel in motor vehicles and power stations
N2(g) + O2(g) → 2NO(g), 2NO(g) + O2(g) → 2NO2(g).
PbS + O2(g) → Pb(s) + SO2(g), incineration of garbage, petroleum refineries and use of sulphur dioxide in industries to produce sulfuric acid, paper, food processing and sewage treatment.
There are a number of oxides of nitrogen and they are represented as NOx, which refers to the NO and NO2 gases in the atmosphere. Nitrogen dioxide is a red-brown gas and is poisonous which makes it harmful to the respiratory system, causing decreased lung function, susceptibility to respiratory infections and increased sensitivity to asthma triggers. Nitrogen dioxide is an acidic oxide. A natural source is the action of sunlight on NO and O2. An industrial source is the combustion of fuel in motor vehicles and power stations. Dinitrogen monoxide is a colourless gas and it is neutral. A natural source of dinitrogen monoxide is produced by soil bacteria. Industrial sources of dinitrogen monoxide are manufactured as a fuel for racing cars and for use as a sedative. Nitrogen monoxide is a colourless gas and it is neutral. A natural source is produced by soil bacteria and lighting
N2(g) + O2(g) → 2NO(g). Industrial sources are produced by the burning of biomass and the combustion of fuel in motor vehicles and power stations
N2(g) + O2(g) → 2NO(g), 2NO(g) + O2(g) → 2NO2(g).
Acid Rain
Acid rain is rain that has a higher hydrogen ion concentration than normal- higher than about 10-5 mol/L. It has a pH lower than 5. Normal rain has pH between 6-6.5, which is slightly acidic because of dissolved acidic oxides. The main natural acidic oxide that makes pH <7 is sulphur dioxide.
Sulphur dioxide reacts to form sulphurous acid, SO2(g) + H2O(l) → H2SO3(aq), impurities in the air catalyse the conversion of sulphurous acid to sulfuric acid, 2H2SO3(aq) + O2(g) → 2H2SO4(aq) (with catalyst), sulfuric acid is soluble in water and so it is removed from the atmosphere by rain.
Nitrogen dioxide reacts with water to form a mixture of nitrous and nitric acids, 2NO2(g) + H2O(l) → HNO2(aq) + HNO3(aq), nitrous acid in solution is catalytically oxidise in nitric acid, 2HNO2(aq) + O2(g) → 2HNO3(aq) (with catalyst), nitric acid is soluble in water and so it is removed from the atmosphere by rain. Neutral oxide NO can also lead to formation of acid rain because it always converts to nitrogen dioxide NO2 in the presence of oxygen.
Acid rain erodes limestone buildings because a chemical reaction occurs between calcium carbonate, the primary component of limestone, and sulfuric acid, which is the primary component of acid rain. This reaction results in the dissolution of calcium carbonate to give aqueous ions, which in turn are washed away in the water flow. CaCO3(s) + H2SO4(aq) → Ca 2+ (aq) + SO4 2- (aq) + H2O(l) + CO2(g).
Acid rain can affect plant growth and cause defoliation, stunted growth and decrease the ability of plants to withstand frost. Sulfuric acid is a major part of acid rain and when in water it ionises, forming hydrogen ions, sulfate ions and hydrogen sulfate ions. The sulfate ions attract calcium and magnesium ions, which occur naturally in the soil and are vital for plant growth, drawing them out and leaving the soil deficient of these essential minerals. In acidic water insoluble compounds in soil such as aluminium sulfate become soluble which releases harmful aluminium ions into the soil and surrounding water. These aluminium ions cause the gills of fish to clog with mucus and die. Acid rain lowers the pH of lakes and streams, killing aquatic life. These problems often occur near cities and places of heavy industry because there is higher concentration of acidic oxides in the atmosphere, which makes the rain more acidic and causes these various problems of erosion and health issues.
Sulphur dioxide reacts to form sulphurous acid, SO2(g) + H2O(l) → H2SO3(aq), impurities in the air catalyse the conversion of sulphurous acid to sulfuric acid, 2H2SO3(aq) + O2(g) → 2H2SO4(aq) (with catalyst), sulfuric acid is soluble in water and so it is removed from the atmosphere by rain.
Nitrogen dioxide reacts with water to form a mixture of nitrous and nitric acids, 2NO2(g) + H2O(l) → HNO2(aq) + HNO3(aq), nitrous acid in solution is catalytically oxidise in nitric acid, 2HNO2(aq) + O2(g) → 2HNO3(aq) (with catalyst), nitric acid is soluble in water and so it is removed from the atmosphere by rain. Neutral oxide NO can also lead to formation of acid rain because it always converts to nitrogen dioxide NO2 in the presence of oxygen.
Acid rain erodes limestone buildings because a chemical reaction occurs between calcium carbonate, the primary component of limestone, and sulfuric acid, which is the primary component of acid rain. This reaction results in the dissolution of calcium carbonate to give aqueous ions, which in turn are washed away in the water flow. CaCO3(s) + H2SO4(aq) → Ca 2+ (aq) + SO4 2- (aq) + H2O(l) + CO2(g).
Acid rain can affect plant growth and cause defoliation, stunted growth and decrease the ability of plants to withstand frost. Sulfuric acid is a major part of acid rain and when in water it ionises, forming hydrogen ions, sulfate ions and hydrogen sulfate ions. The sulfate ions attract calcium and magnesium ions, which occur naturally in the soil and are vital for plant growth, drawing them out and leaving the soil deficient of these essential minerals. In acidic water insoluble compounds in soil such as aluminium sulfate become soluble which releases harmful aluminium ions into the soil and surrounding water. These aluminium ions cause the gills of fish to clog with mucus and die. Acid rain lowers the pH of lakes and streams, killing aquatic life. These problems often occur near cities and places of heavy industry because there is higher concentration of acidic oxides in the atmosphere, which makes the rain more acidic and causes these various problems of erosion and health issues.
Evidence of Anthropogenic Sources of Acidic Oxides
Emissions of SO2 and NOx first started to increase after the industrial revolution of the early 1800’s. In the 1950’s there were a series of nasty pollution episodes in London and the northeast of the USA, which cause many deaths. This brought about the introduction of air quality regulations for SO2. Factors that increased the NOx emissions in the 20th century included the increased use of motorcars and electricity generation. In the 1960’s photochemical smog became a problem in many sunny cities, which led to the introduction of air quality regulations for NOx.
Strategies that can be used to limit SO2 and NOx emissions include reducing the amount of coal being burnt, power companies burning low-sulphur coal rather than high-sulphur coal, switching to natural gas which produces very little sulphur dioxide in combustion, reducing our reliance on fossil fuels by developing other forms of power, collecting the sulphur dioxide produced by smelting metal sulphides and using it to make sulfuric acid, reducing acidic emissions from smoke stacks by using a process called ‘scrubbing’ and ensuing exhausts from motor vehicles pass through a catalytic convertor. SO2 and NOx in large cities and urban areas continues to increase because of growing population within these areas and a heavy reliance and demand for motor vehicles, electricity and metals, all of which cause and produce acidic oxides such as SO2 and NOx which are released into the atmosphere.
The recent effects of acid rain near industrial centres can be considered evidence of increased SO2 and NOx in the atmosphere because of its serve effects and damage. Acid rain itself is an indicator of increased SO2 and NOx. If there is acid rain damage near industrial centres it is logical to assume that there is increased SO2 and NOx in the atmosphere, which is causing this acid rain and its severely damaging effects.
Over the past 150 years global CO2 concentration has greatly increased overall. Ice core samples shown that over the past 100 years carbon dioxide concentrations have increased from 280ppm before industrialisation to 379ppm now. The graph of the atmospheric carbon dioxide concentration at Mauna Loa observatory shows that even though in summer there is a drop in atmospheric carbon dioxide compared to the winter, over the past 50 years there has been a steady increase in the amount of carbon dioxide present in the atmosphere. Evidence that suggests Global SO2 and NOx concentrations have also been increasing over the past 150 years include ice core samples and damage. Ice core samples show that dinitrogen monoxide has increased about 10%. Increased damage to buildings, forests and aquatic organisms provides evidence of recent atmospheric changes.
It has been difficult to accurately measure SO2 and NOx concentrations in the atmosphere because sulphur dioxide and nitrogen dioxide form sulfate and nitrate ions respectively, which are mostly soluble in water. These circulate in the biosphere and hydrosphere but are not precipitated out in forms we can readily study. Another reason is that sulphur and nitrogen oxides are present in much smaller concentrations and instruments capable of measuring these small concentrations have only been available since the 1970’s.
Over the past 100 years there has been a significant increase in SO2 and NOx, but there is not enough evidence to suggest that this could be a consequence of natural emissions rather than human activity. Evidence that suggests there has been a human caused increase in SO2 and NOx over the past 100 years is that SO2 and NOx levels did not start to significantly increase in the atmosphere until the industrial revolution, which saw a huge increase in human activity. Since the invention of equipment capable of accurately measuring SO2 and NOx levels, it has been shown that areas near cities and industrial sites show significantly higher levels of SO2 and NOx than non-industrial areas. This evidence shows that human industrial activity has produced a significant increase in SO2 and NOx levels. There is little evidence to suggest there has been an anthropogenic increase in SO2 and NOx over the past 100 years, especially because until the 1970’s there was not equipment that was sophisticated enough to accurately measure the levels of SO2 and NOx in the atmosphere, so therefor we cannot assume that this increase in SO2 and NOx is a naturally occurring thing but rather something that has been influence by human activity. There is not enough evidence to suggest an anthropogenic increase in SO2 and NOx over the past 100 years but rather a human caused increase in the atmospheric levels of SO2 and NOx over the past 100 years.
Strategies that can be used to limit SO2 and NOx emissions include reducing the amount of coal being burnt, power companies burning low-sulphur coal rather than high-sulphur coal, switching to natural gas which produces very little sulphur dioxide in combustion, reducing our reliance on fossil fuels by developing other forms of power, collecting the sulphur dioxide produced by smelting metal sulphides and using it to make sulfuric acid, reducing acidic emissions from smoke stacks by using a process called ‘scrubbing’ and ensuing exhausts from motor vehicles pass through a catalytic convertor. SO2 and NOx in large cities and urban areas continues to increase because of growing population within these areas and a heavy reliance and demand for motor vehicles, electricity and metals, all of which cause and produce acidic oxides such as SO2 and NOx which are released into the atmosphere.
The recent effects of acid rain near industrial centres can be considered evidence of increased SO2 and NOx in the atmosphere because of its serve effects and damage. Acid rain itself is an indicator of increased SO2 and NOx. If there is acid rain damage near industrial centres it is logical to assume that there is increased SO2 and NOx in the atmosphere, which is causing this acid rain and its severely damaging effects.
Over the past 150 years global CO2 concentration has greatly increased overall. Ice core samples shown that over the past 100 years carbon dioxide concentrations have increased from 280ppm before industrialisation to 379ppm now. The graph of the atmospheric carbon dioxide concentration at Mauna Loa observatory shows that even though in summer there is a drop in atmospheric carbon dioxide compared to the winter, over the past 50 years there has been a steady increase in the amount of carbon dioxide present in the atmosphere. Evidence that suggests Global SO2 and NOx concentrations have also been increasing over the past 150 years include ice core samples and damage. Ice core samples show that dinitrogen monoxide has increased about 10%. Increased damage to buildings, forests and aquatic organisms provides evidence of recent atmospheric changes.
It has been difficult to accurately measure SO2 and NOx concentrations in the atmosphere because sulphur dioxide and nitrogen dioxide form sulfate and nitrate ions respectively, which are mostly soluble in water. These circulate in the biosphere and hydrosphere but are not precipitated out in forms we can readily study. Another reason is that sulphur and nitrogen oxides are present in much smaller concentrations and instruments capable of measuring these small concentrations have only been available since the 1970’s.
Over the past 100 years there has been a significant increase in SO2 and NOx, but there is not enough evidence to suggest that this could be a consequence of natural emissions rather than human activity. Evidence that suggests there has been a human caused increase in SO2 and NOx over the past 100 years is that SO2 and NOx levels did not start to significantly increase in the atmosphere until the industrial revolution, which saw a huge increase in human activity. Since the invention of equipment capable of accurately measuring SO2 and NOx levels, it has been shown that areas near cities and industrial sites show significantly higher levels of SO2 and NOx than non-industrial areas. This evidence shows that human industrial activity has produced a significant increase in SO2 and NOx levels. There is little evidence to suggest there has been an anthropogenic increase in SO2 and NOx over the past 100 years, especially because until the 1970’s there was not equipment that was sophisticated enough to accurately measure the levels of SO2 and NOx in the atmosphere, so therefor we cannot assume that this increase in SO2 and NOx is a naturally occurring thing but rather something that has been influence by human activity. There is not enough evidence to suggest an anthropogenic increase in SO2 and NOx over the past 100 years but rather a human caused increase in the atmospheric levels of SO2 and NOx over the past 100 years.
Evaluating Concern about Acidic oxides
SO2 occurs naturally in the atmosphere through combustion of organic matter, decomposition of organic matter and volcanoes S(s) + O2(g) → SO2(g). A natural source of NO2 is from the reaction of sunlight on NO and O2. N2O is produced naturally by soil bacteria. A natural source of NO is produced by soil bacteria and lighting N2(g) + O2(g) → 2NO(g). Industrial sources of SO2 include combustion of fuels, metal smelters extracting zinc, copper and lead from Sulfides PbS + O2(g) → Pb(s) + SO2(g) , incineration of garbage, petroleum refineries and use of sulphur dioxide in industries to produce sulfuric acid, paper, food processing and sewage treatment. An industrial source of NO2 is the combustion of fuel in motor vehicles and power stations. Industrial sources of N2O are manufactured as a fuel for racing cars and for use as a sedative. Industrial sources of NO are produced by the burning of biomass and the combustion of fuel in motor vehicles and power stations N2(g) + O2(g) → 2NO(g), 2NO(g) + O2(g) → 2NO2(g).
Sulphur dioxide reacts to form sulphurous acid, SO2(g) + H2O(l) → H2SO3(aq), impurities in the air catalyse the conversion of sulphurous acid to sulfuric acid, 2H2SO3(aq) + O2(g) → 2H2SO4(aq) (with catalyst), sulfuric acid is soluble in water and so it is removed from the atmosphere by rain.
Nitrogen dioxide reacts with water to form a mixture of nitrous and nitric acids, 2NO2 (g) + H2O (l) → HNO2 (aq) + HNO3 (aq), nitrous acid in solution is catalytically oxidise in nitric acid, 2HNO2(aq) + O2(g) → 2HNO3(aq) (with catalyst), nitric acid is soluble in water and so it is removed from the atmosphere by rain.
Acid rain is rain that has a higher hydrogen ion concentration than normal- higher than about 10-5 mol/L. It has a pH lower than 5. Acid rain erodes limestone buildings CaCO3(s) + H2SO4(aq) → Ca 2+ (aq) + SO4 2- (aq) + H2O(l) + CO2(g). Acid rain can affect plant growth and cause defoliation, stunted growth and decrease the ability of plants to withstand frost. Sulfuric acid is a major part of acid rain and when in water it ionises, forming hydrogen ions, sulfate ions and hydrogen sulfate ions. The sulfate ions attract calcium and magnesium ions, which occur naturally in the soil and are vital for plant growth, drawing them out and leaving the soil deficient of these essential minerals. In acidic water insoluble compounds in soil such as aluminium sulfate become soluble which releases harmful aluminium ions into the soil and surrounding water. These aluminium ions cause the gills of fish to clog with mucus and die. Acid rain lowers the pH of lakes and streams, killing aquatic life.
There is little evidence to suggest anthropogenic sources are the cause for the increased atmospheric levels of SO2 and NOx. This is due to not having technology sophisticated enough until recently to accurately measure atmospheric levels of SO2 and NOx and also the difficulty in measuring past atmospheric levels of SO2 and NOx because these substances are soluble in water and so dissolve and wash away in rain.
There is not sufficient evidence to be able to suggest that the increased atmospheric levels of SO 2and NOx are caused by anthropogenic sources but there is evidence to suggest that it has been caused by human activity. This means that we need to implement strategies to reduce the atmospheric levels of SO2 and NOx and return them to there natural amounts. Strategies that can be used to limit SO2 and NOx emissions include reducing the amount of coal being burnt, power companies burning low-sulphur coal rather than high-sulphur coal, switching to natural gas which produces very little sulphur dioxide in combustion, reducing our reliance on fossil fuels by developing other forms of power, collecting the sulphur dioxide produced by smelting metal sulphides and using it to make sulfuric acid, reducing acidic emissions from smoke stacks by using a process called ‘scrubbing’ and ensuing exhausts from motor vehicles pass through a catalytic convertor. The problem of acid rain and increased acidic oxides in the atmosphere will continue to get worse because growing populations will mean increased demand for electricity and motor vehicles, which are both major contributors to increased atmospheric levels of acidic oxides. A strategy that has been effective in reducing emissions of SO2 and NOx is placing air quality regulations on large factory’s and industries. The problem of increased acidic oxides in the atmosphere is very serious as it can result in environmental problems, health problems and even death. The evidence that suggest s the increased atmospheric levels of SO2 and NOx are caused by human activity means that we should be concerned about SO2 and NOx emissions because they can have serve environmental and human health issues, and also because we as humans have caused them it means that we can do something and implement strategies to reduce acidic oxides in the atmosphere.
Sulphur dioxide reacts to form sulphurous acid, SO2(g) + H2O(l) → H2SO3(aq), impurities in the air catalyse the conversion of sulphurous acid to sulfuric acid, 2H2SO3(aq) + O2(g) → 2H2SO4(aq) (with catalyst), sulfuric acid is soluble in water and so it is removed from the atmosphere by rain.
Nitrogen dioxide reacts with water to form a mixture of nitrous and nitric acids, 2NO2 (g) + H2O (l) → HNO2 (aq) + HNO3 (aq), nitrous acid in solution is catalytically oxidise in nitric acid, 2HNO2(aq) + O2(g) → 2HNO3(aq) (with catalyst), nitric acid is soluble in water and so it is removed from the atmosphere by rain.
Acid rain is rain that has a higher hydrogen ion concentration than normal- higher than about 10-5 mol/L. It has a pH lower than 5. Acid rain erodes limestone buildings CaCO3(s) + H2SO4(aq) → Ca 2+ (aq) + SO4 2- (aq) + H2O(l) + CO2(g). Acid rain can affect plant growth and cause defoliation, stunted growth and decrease the ability of plants to withstand frost. Sulfuric acid is a major part of acid rain and when in water it ionises, forming hydrogen ions, sulfate ions and hydrogen sulfate ions. The sulfate ions attract calcium and magnesium ions, which occur naturally in the soil and are vital for plant growth, drawing them out and leaving the soil deficient of these essential minerals. In acidic water insoluble compounds in soil such as aluminium sulfate become soluble which releases harmful aluminium ions into the soil and surrounding water. These aluminium ions cause the gills of fish to clog with mucus and die. Acid rain lowers the pH of lakes and streams, killing aquatic life.
There is little evidence to suggest anthropogenic sources are the cause for the increased atmospheric levels of SO2 and NOx. This is due to not having technology sophisticated enough until recently to accurately measure atmospheric levels of SO2 and NOx and also the difficulty in measuring past atmospheric levels of SO2 and NOx because these substances are soluble in water and so dissolve and wash away in rain.
There is not sufficient evidence to be able to suggest that the increased atmospheric levels of SO 2and NOx are caused by anthropogenic sources but there is evidence to suggest that it has been caused by human activity. This means that we need to implement strategies to reduce the atmospheric levels of SO2 and NOx and return them to there natural amounts. Strategies that can be used to limit SO2 and NOx emissions include reducing the amount of coal being burnt, power companies burning low-sulphur coal rather than high-sulphur coal, switching to natural gas which produces very little sulphur dioxide in combustion, reducing our reliance on fossil fuels by developing other forms of power, collecting the sulphur dioxide produced by smelting metal sulphides and using it to make sulfuric acid, reducing acidic emissions from smoke stacks by using a process called ‘scrubbing’ and ensuing exhausts from motor vehicles pass through a catalytic convertor. The problem of acid rain and increased acidic oxides in the atmosphere will continue to get worse because growing populations will mean increased demand for electricity and motor vehicles, which are both major contributors to increased atmospheric levels of acidic oxides. A strategy that has been effective in reducing emissions of SO2 and NOx is placing air quality regulations on large factory’s and industries. The problem of increased acidic oxides in the atmosphere is very serious as it can result in environmental problems, health problems and even death. The evidence that suggest s the increased atmospheric levels of SO2 and NOx are caused by human activity means that we should be concerned about SO2 and NOx emissions because they can have serve environmental and human health issues, and also because we as humans have caused them it means that we can do something and implement strategies to reduce acidic oxides in the atmosphere.