Essays academic service


The process of salting reduces the effects of acid rain

Thus, a large increase in the concentration of NO and SO2 significantly affects the pH of rainwater, even though both gases are present at much lower concentration than CO2.

About one-fourth of the acidity of rain is accounted for by nitric acid HNO3. In the process of salting reduces the effects of acid rain to the natural processes that form small amounts of nitric acid in rainwater, high-temperature air combustion, such as occurs in car engines and power plants, produces large amounts of NO gas.

This gas then forms nitric acid via Equations 4 and 5. Thus, a process that occurs naturally at levels tolerable by the environment can harm the environment when human activity causes the process e.

Most is accounted for by the presence of sulfuric acid H2SO4 in rainwater. Although sulfuric acid may be produced naturally in small quantities from biological decay and volcanic activity Figure 1it is produced almost entirely by human activity, especially the combustion of sulfur-containing fossil fuels in power plants.

When these fossil fuels are burned, the sulfur contained in them reacts with oxygen from the air to form sulfur dioxide SO2. The effects of burning fossil fuels can be dramatic: Sulfur dioxide, like the oxides of carbon and nitrogen, reacts with water to form sulfuric acid Equation 6.

At sea level and 25oC, one mole of air fills a volume of 24. Compute the mole fraction i. One strategy for limiting the amount of acid pollution in the atmosphere is scrubbing. In particular, calcium oxide CaO is injected into the combustion chamber of a power plant, where it reacts with the sulfur dioxide produced, to yield solid calcium sulfite.

Write a balanced chemical equation for this reaction. Consult the table of common ions in the tutorial assignment for Experiment 1 to view the structure and formula for sulfite; also, use your knowledge of the periodic table to deduce the charge of the calcium ion. Using these facts, you can deduce the formula for calcium sulfite. Approximately one ton, or 9. The final stage in the scrubbing process is to treat the combustion gases with a slurry of solid CaO in water, in order to trap any remaining SO2 and convert it to calcium sulfite.

What Causes Acid Rain?

A slurry is a thick suspension of an insoluble precipitate in water. Using the solubility guidelines provided the process of salting reduces the effects of acid rain the lab manual for this experiment, predict whether this stage of the scrubbing process will produce a slurry i.

If MgO, rather than CaO, were used for scrubbing, would the product of the final stage be a slurry or a solution of magnesium sulfite?

Assume that a very large quantity of magnesium sulfite, relative to the amount of water, is produced. Environmental Effects of Acid Rain Acid rain triggers a number of inorganic and biochemical reactions with deleterious environmental effects, making this a growing environmental problem worldwide. Many lakes have become so acidic that fish cannot live in them anymore. Degradation of many soil minerals produces metal ions that are then washed away in the runoff, causing several effects: Atmospheric pollutants are easily moved by wind currents, so acid-rain effects are felt far from where pollutants are generated.

Stone Buildings and Monuments in Acid Rain Marble and limestone have long been preferred materials for constructing durable buildings and monuments. Marble and limestone both consist of calcium carbonate CaCO3and differ only in their crystalline structure.

Limestone consists of smaller crystals and is more porous than marble; it is used more extensively in buildings. Marble, with its larger crystals and smaller pores, can attain a high polish and is thus preferred for monuments and statues. Although these are recognized as highly durable materials, buildings and outdoor monuments made of marble and limestone are now being gradually eroded away by acid rain.

How does this happen? A chemical reaction Equation 9 between calcium carbonate and sulfuric acid the primary acid component of acid rain results in the dissolution of CaCO3 to give aqueous ions, which in turn are washed away in the water flow. The degree of damage is determined not only by the acidity of the rainwater, but also by the amount of water flow that a region of the surface receives.

Regions exposed to direct downpour of acid rain are highly susceptible to erosion, but regions that are more sheltered from water flow such as under eaves and overhangs of limestone buildings are much better preserved.

  • Most lakes and streams have a pH level between six and eight;
  • Many of these species lay their eggs in the water to hatch;
  • Compute the mole fraction i;
  • A slurry is a thick suspension of an insoluble precipitate in water.

The marble columns of the emperors Marcus Aurelius and Trajan, in Rome, provide a striking example: Even those parts of marble and limestone structures that are not themselves eroded can be damaged by this process Equation 9. When the water dries, it leaves behind the ions that were dissolved in it.

What is Acid Rain?

When a solution containing calcium and sulfate ions dries, the ions crystallize as CaSO4l 2H2O, which is gypsum. Gypsum is soluble in water, so it is washed away from areas that receive a heavy flow of rain. However, gypsum accumulates in the same sheltered areas that are protected from erosion, and attracts dust, carbon particles, dry-ash, and other dark pollutants.

This results in blackening of the surfaces where gypsum accumulates. An even more serious situation arises when water containing calcium and sulfate ions penetrates the stone's pores.

  • The amphibian embyos have membranes that are too tough because of the acids, such that they are unable to break through at the proper time;
  • The pollutants attack humans indirectly through the foods they consumed;
  • The authors thank Dewey Holten Washington University for many helpful suggestions in the writing of this tutorial;
  • Marble, limestone, and sandstone can easily be dissolved by acid rain;
  • Meaning, it is successful in removing pyritic sulfur due to its high specific gravity, but it is unsuccessful in removing chemically bound organic sulfur;
  • In addition to the natural processes that form small amounts of nitric acid in rainwater, high-temperature air combustion, such as occurs in car engines and power plants, produces large amounts of NO gas.

When the water dries, the ions form salt crystals within the pore system. These crystals can disrupt the crystalline arrangement of the atoms in the stone, causing the fundamental structure of the stone to be disturbed. If the crystalline structure is disrupted sufficiently, the stone may actually crack.

Thus, porosity is an important factor in determining a stone's durability. Questions on Effects of Acid Rain 6. Based on the information described above about the calcium ion, and the formula of calcium carbonate CaCO3deduce the charge of the carbonate ion. Also, in the structure of the carbonate ion, are any of the oxygens bonded to one another, or all the oxygens bonded to the carbon atom?

Consult the structure of the common ions given in the tutorial for Experiment 1. Write the net ionic equation for the reaction of calcium carbonate and sulfuric acid. See the introduction to Experiment 2 in the lab manual for a discussion of net ionic equations. Which is a more durable building material, limestone or marble? Briefly, explain your reasoning. The Environmental Protection Agency's site on acid rain presents the basics of this problem in an accessible format. The National Atmospheric Deposition Program features isopleth maps showing the concentrations of many different pollutants throughout the country.

One more step

Another very interesting EPA site on acid rain explains the novel "allowance trading system" strategy for getting companies to control their sulfur dioxide emissions. Brown, Lemay, and Buster. Upper Saddle River, NJ: Principles and Modern Applications, 7th ed. New England Water Works Assn. The authors thank Dewey Holten Washington University for many helpful suggestions in the writing of this tutorial.