The main cause of acid rain is the presence of

Earth sulfur dioxide SO 2 and nitrogen dioxide NO 2 , which as a result

chemical reactions occurring in the atmosphere are converted into, respectively

sulfuric and nitric acids, the fall of which on the surface of the earth has

influence on living organisms and the ecotype as a whole.

Acid rain corrodes metals, paints, synthetic compounds, and destroys architectural monuments. Plants suffer the most from acid rain. However, the acid does not directly damage the trees. Acid precipitation causes leaf diseases and acidifies the soil, leaching nutrients from it and saturating it with toxic compounds.

The impact of acid rain on humans is also not only direct. Of course, microparticles of sulfates and nitrates contained in the air increase the risk of an asthma attack, bronchitis, and harm the cardiovascular system. Fish also die due to acid rain.

One of the main methods of control is the installation at each enterprise of expensive treatment facilities, the filters of which will prevent the emissions of heavy metals and hazardous oxides.
Another way to solve the problem is to reduce the number of vehicles in large cities in order to reduce exhaust emissions.
In addition, forests should be restored rather than cut down, polluted water bodies should be cleaned, and garbage should be recycled rather than burned.

Presentation on the topic: Acid rain - a pressing environmental problem

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Presentation on the topic: Acid rain is a pressing environmental problem

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The first mention of acid rain dates back to the middle of the 19th century. In 1872, the attention of English explorer Angus Smith was drawn to Victorian smog in Manchester. However, the global danger of the phenomenon was realized only in the 60s. XX century Scandinavian countries, Canada, the USA, Western Europe, etc. suffered from acid rain. Therefore, this problem was raised by Switzerland at the UN Conference on the Environment (Stockholm, 1972).

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Sources of acid-forming emissions Natural sources supply sulfur and nitrogen to the atmosphere (cycles in the biosphere, volcanic activity, etc.). However, anthropogenic factors play a major role. Emissions of these compounds from economic activities (fossil fuel power plants, metallurgical enterprises, etc.) amount to 255 million tons. In Europe alone, emissions of sulfur dioxide in some years reach 20-40 million tons. In Russia, stationary sources released more than 7 million tons of acid-forming substances into the atmosphere. As a result of transboundary transfer, about 2 million tons of oxidized sulfur and nitrogen compounds entered the European part of the country.

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Sources of acid-forming emissions Solid fuel rockets Shuttle, Proton and Energia make a certain contribution to the formation of acid precipitation. Acid traces are formed from the combustion products of rocket fuel, consisting of particles of hydrogen chloride, nitrogen oxide, aluminum oxide, etc. Thus, during one launch of the Shuttle rocket complex, 225 tons of hydrogen chloride, about 88 tons of nitrogen oxides, and 310 tons of aluminum oxide enter the atmosphere.

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Formation of acid rain. Sulfur dioxide released into the atmosphere undergoes a series of chemical transformations leading to the formation of acids. Partially, sulfur dioxide as a result of photochemical oxidation is converted into sulfur oxide (VI) (sulfuric anhydride) SO3: 2 SO2 + O2 ↔ 2 SO3, which reacts with atmospheric water vapor, forming aerosols of sulfuric acid: SO3 + H2O → H2 SO4H2SO4 ↔ H+ + HSO4 -The main part of the emitted sulfur dioxide in humid air forms acidic polyhydrate SO2 nH2O, which is often called sulfurous acid H2 SO3:SO2 + H2O → H2 SO3H2SO3 ↔ H+ + HSO3 -Sulfurous acid in humid air is gradually oxidized to sulfuric acid: 2H2 SO3 + O2 → 2 H2 SO4 Aerosols of sulfuric and sulfurous acids condense in atmospheric water vapor and cause acid precipitation. They make up about 2/3 of acid precipitation. The rest is accounted for by aerosols of nitric and nitrous acids formed during the interaction of nitrogen dioxide with atmospheric water vapor: 2NO2 + H2O→ HNO3 + HNO2 HNO3 ↔ H+ +NO3-HNO2 ↔ H+ +NO2-

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Negative ecological and biological consequences of acid rain: Deterioration of atmospheric visibility Acidification of freshwater bodies and reduction of fish stocks Acidification of soils and reduction of their fertility Damage and death of forest formations Destruction of certain species of animals Acceleration of corrosion of bridges, dams, metal structures Harm to human health Acceleration of destruction of world architectural monuments

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Acidification of lakes Freshwater lakes in Canada, the USA, Sweden, Norway, Finland, Russia and other countries have suffered from acid precipitation. Thus, in Canada, more than 14,000 lakes are acidified, in the eastern part of the USA - about 9,000, in Sweden - more than 6,500 reservoirs, in Norway - 5,000. In Russia, the lakes of Karelia and the Kola Peninsula were especially affected by acid precipitation. On the Kola Peninsula, 37% of the surveyed lakes are highly acidified, and about 30% of water bodies are at risk of acidification. In many lake ecosystems, an increase in water acidity (a decrease in pH value) has led to the degradation of fish populations and other aquatic organisms.

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Soil acidification Acid rain has a negative impact on soils: - Reduces soil fertility. At a pH value less than 5.0, a progressive decrease in their fertility begins, and at pH = 3, they become practically infertile. - Reduce the rate of decomposition of organic matter. Most bacteria and fungi prefer a neutral environment. At pH = 6.2, the number of bacteria in 1 g of soil is 13.6 x 106, and at pH = 4.8 - 4 x 106. - They wash out many nutrients from the soil. This leads to a decrease in the yield of agricultural crops (cotton, tomatoes, grapes, citrus fruits, etc.) by an average of 20-30%. Russia, which has more than 50 million hectares of acidified soils, annually loses agricultural yields in the amount of 16-18 million . tons in terms of grain.

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Impact on forest formations Due to precipitation: - plant growth has decreased and natural reforestation has deteriorated; - plant resistance to drought, frost and salinity has decreased; - the processes of transpiration, respiration and photosynthesis were disrupted. An increase in the area of damaged and dead forests was noted in Europe: in 1860 they occupied about 1000 hectares, now - over 50 million hectares. In Russia, outbreaks of pests and diseases annually cover up to 4 million hectares of forest formations. In Sweden, Spain, Austria, the share of degraded forests is 22-39%, in the Czech Republic, Slovakia, Greece, Great Britain, Norway - it reaches 49-71% of the total forest area. In Western Europe, coniferous species (Norway spruce) are particularly affected by acidification. The supply of sulfur and nitrogen compounds changes the chemical composition of soils and the nutritional regime of plants. Violation of the diet leads to discoloration and drying out of conifers. This process affected not only coniferous species, but also broad-leaved formations (oak, beech, sycamore, hickory, etc.).

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Harm to human health Aerosol particles from acid deposition pose a particular danger to human health. Large particles are retained in the upper respiratory tract. Small (less than 2 microns) droplets, consisting of a mixture of sulfuric and nitric acids, penetrate into the most remote areas of the lungs. With these aerosols, carcinogenic heavy metals (mercury, cadmium, lead) can enter the body. Thus, during the tragic London fog of 1952, more than 4,000 deaths were attributed to the increased content of sulfur oxides and sulfate particles in the humid air. In acidified lakes of the USA, Norway, and Finland, high concentrations of mercury in fish tissues were noted. The harm that eating such fish causes to the body is obvious; when consumed, it causes various diseases contaminated with acids (Minamata disease) in people. precipitation of water.

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Damage to world architectural monuments Due to acid precipitation, the Colosseum and St. Peter's Cathedral in Rome, St. Mark's Cathedral in Venice, Delphi (the sanctuary of Apollo), temples and tombs in industrial areas of Japan, etc. are destroyed. The huge stone obelisk of Cleopatra, transported from Egypt to Great Britain, suffered more severe damage due to acid precipitation during its 85 years in London than in 3,000 years in Alexandria. The leader in the impact of acid rain on buildings and architectural structures in Western Europe is Manchester, where in 20 months. acid precipitation dissolved more than 120 g of stone (sandstone, marble, limestone) from 1 m2 of structures. Next come Antwerp (Netherlands) - losses of more than 100 g/m2 - and cities such as Athens, Amsterdam, Copenhagen, where acid rain dissolved 20-40 g of stone from every 1 m2 of construction. (According to the University of Dublin (Ireland)

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Today, no one doubts that acid rain is one of the causes of the death of life in water bodies, forests, crops, and vegetation. In addition, acid rain destroys buildings and cultural monuments, pipelines, renders cars unusable, reduces soil fertility and can lead to toxic metals leaking into aquifers.

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Acid precipitation

causes and consequences

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Acid precipitation is precipitation whose acidity is higher than normal. A measure of acidity is the pH value (hydrogen value). The pH value scale goes from 0 (extremely high acidity), through 7 (neutral environment, i.e. pure water) to 14 (alkaline environment). The lower the pH value, the higher the acidity. If the acidity of the water is below 5.5, then the precipitation is considered acidic. Over vast areas of the industrialized countries of the world, precipitation falls, the acidity of which exceeds normal by 10 - 1000 times (pH = 5-2.5). The term “acid rain” was first introduced in 1872 by the English scientist Robert Smith in his book Air and Rain: The Beginning of Chemical Climatology. The smog in Manchester caught his attention.

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Causes

Even normal rainwater is slightly acidic due to the presence of carbon dioxide in the air. And acid rain is formed by a reaction between water and pollutants such as sulfur oxide and various nitrogen oxides. These substances are emitted into the atmosphere by road transport, as a result of the activities of metallurgical enterprises and thermal power plants. Combining with atmospheric water, they turn into solutions of acids - sulfuric, sulfurous, nitrous and nitric. Then, along with snow or rain, they fall to the ground.

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Consequences

The consequences of acid rain are observed in the USA, Germany, the Czech Republic, Slovakia, the Netherlands, Switzerland, Australia, the republics of the former Yugoslavia and many other countries around the globe. Death of reservoirs and aquatic inhabitants; Forest degradation; Soil erosion; Release of Al, Hg and Cu from rocks and minerals.

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Measures to prevent acid precipitation

To combat acid rain, efforts must be directed toward reducing emissions of acid-forming substances from coal-fired power plants. And for this it is necessary: the use of low-sulfur coal or its removal of sulfur; installation of filters for purification of gaseous products; use of alternative energy sources.

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Thank you for your attention!

Presentation on the topic "Acid rain" in chemistry in powerpoint format. The presentation talks about the processes of sulfur combustion, the formation of acid rain and their effect on plants.

Fragments from the presentation

Sulfur and nitrogen oxides are formed during the combustion of coal, oil, and during the operation of cars. Sulfur dioxide is also released during volcanic eruptions.
Dissolving in atmospheric moisture, they cause “acid rain”, which affects vegetation, destroys living organisms in water bodies, causes illness in people, and destroys metal structures and building materials.
Therefore, it is very important to understand the cause of acid rain and learn how to prevent its occurrence.

Goal of the work

Study the processes of sulfur combustion: a) in air, b) in oxygen
Study the dissolution of sulfur combustion products in water
Find out how acid rain is formed
Study their effect on plants

What is needed for the experiment Burning sulfur in the air:

Sulfur color (sulfur powder)
Glass cylinder
Burning spoon
Watch glass
Alcohol lamp
Take sulfur powder into a spoon
Light the sulfur in a spoon in the flame of an alcohol lamp
We bring a spoon with burning sulfur into the cylinder
We observe white smoke from burning sulfur

Adding water

What is needed for the experiment Combustion of sulfur in oxygen:

Sulfur color (sulfur powder)
Hydrogen peroxide and manganese dioxide (to produce oxygen)
Glass cylinder
Burning spoon
Watch glass
Alcohol lamp
Green plant leaf (chlorophytum)
Pour approximately 10 ml of hydrogen peroxide solution into the cylinder, add manganese dioxide
The release of oxygen begins according to the reaction 2H2O2 = 2H2O + O2 (manganese dioxide is a catalyst for the reaction)
Pour sulfur into a spoon and set it on fire in the flame of an alcohol lamp.
We introduce a spoon with lit sulfur into the cylinder and oxygen
Sulfur burns with a bright purple flame
White smoke is produced

Adding water

Using a rinser, pour water into the cylinder
Place a leaf of the green plant Chlorophytum into the resulting solution.
Cover the cylinder with a watch glass and leave for a day

In a day

The photo shows how severely damaged the leaves of chlorophytum are when exposed to “acid rain”

Added litmus, chalk and magnesium

Using a pipette, drop 2 drops of “acid rain”, a solution of sulfur combustion products in water, onto strips of red and blue litmus paper
Dropping “acid rain” onto a piece of chalk
Dripping “acid rain” onto magnesium shavings
Red litmus paper remained unchanged, but blue litmus paper turned red
The chalk bubbles, carbon dioxide is released
Magnesium began to dissolve and hydrogen was released

conclusions

During the experiment, oxidation of sulfur dioxide to sulfur trioxide does not occur. But this reaction occurs in the atmosphere and in industry when heated in the presence of a catalyst.
Acid rain destroys plant cells and dissolves magnesium and chalk.
Metal parts and architectural monuments, if they are constantly exposed to acid rain, will be destroyed (due to corrosion).
To prevent acid rain, sulfur dioxide impurities must be captured (from the pipe).

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Slide captions:

The ancient buildings of the Acropolis in Athens suffered more from air pollution during the period from 1960 to 1980 than in the previous two and a half millennia. What explains this? City of El Tajin (Mexico) 6th century BC. Ancient temples of Greece

For the same reason, several years ago, all original marble statues, which are works of art, were removed from the Summer Garden in St. Petersburg and replaced with copies.

Acid rain

Key Questions 1. What is “acid rain”? 2. How does human activity affect the formation of “acid rain”? Main sources of pollution. 3. What effect does acid rain have on the environment? 4 . Can humans prevent air pollution?

Scheme of formation of “acid rain”

The main sources of air pollution are oil refineries, chemical and metallurgical plants, thermal power plants, road transport, textile and food factories.

How are acids formed SO2 + H2O = H2SO3 2 SO2 + O2 = 2 SO3 SO3 + H2O = H2SO4 4NO2 + O2 + 2 H2O = 4HNO3

Experimental results Reagents Water Liquid from the flask Violet flowers No changes Color change Chalk or marble No changes Intense gas release Magnesium Very weak gas release Intense gas release

How you can prevent air pollution Installing purification devices Replacing high-sulfate fuels Controlling automobile emissions Using environmentally friendly fuels

Conclusions Acid rain is the result of air pollution Acid rain destroys not only buildings and cultural monuments, but also destroys all living things Preventing acid rain is the work of man

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