Rain

This essay has a total of 3097 words and 11 pages.

Rain



Acid Rain

Acid Rain Introduction Acid rain has become an environmental concern of global importance
within the last decade. With the increasing environmental awareness of the "unhealthy" condition
of our planet earth the concern about acid rain has not lessened. In brief, acid rain is rain with pH
values of less than 5.6. When dealing with acid rain one must study and understand the process of
making Sulfuric acid. In this project we will take an in depth look into the production of sulfuric
acid, some of its uses and the effects of it as a pollutant in our environment. Sulfuric Acid
Industry in Ontario Among the many plants in Ontario where sulfuric acid is produced, there are
three major plant locations that should be noted on account of their greater size. These are: Inco.
- Sudbury Noranda Mines Ltd. - Welland Sulfide - Ontario There are a number of factors which
govern the location of each manufacturing plant. Some of these factors that have to be considered
when deciding the location of a Sulfuric Acid plant are: a. Whether there is ready access to raw
materials; b. Whether the location is close to major transportation routes; c. Whether there is a
suitable work force in the area for plant construction and operation; d. Whether there is sufficient
energy resources readily available; e. Whether or not the chemical plant can carry out its operation
without any unacceptable damage to the environment. Listed above are the basic deciding factors
that govern the location of a plant. The following will explain in greater detail why these factors
should be considered. 1) Raw Materials The plant needs to be close to the raw materials that are
involved in the production of sulfuric acid such as sulfur, lead, copper, zinc sulfides, etc.. 2)
Transportation A manufacturer must consider proximity to transpor-tation routes and the location
of both the source of raw materials and the market for the product. The raw materials have to be
transported to the plant, and the final product must be transported to the customer or distributor.
Economic pros and cons must also be thought about. For example, must sulfuric plants are
located near the market because it costs more to transport sulfuric acid than the main raw
materials, sulfur. Elaborate commission proof container are required for the transportation of
sulfuric acid while sulfur can be much more easily transported by truck or railway car. 3) Human
Resources For a sulfuric acid plant to operate, a large work force will obviously be required. The
plant must employ chemists, technicians, administrators, computer operators, and people in sales
and marketing. A large number of workers will also be required for the daily operation of the
plant. A work force of this diversity is therefore likely to be found only near major centres of
population. 4) Energy Demands Large amounts of energy will also be required for the production
of many industrial chemicals. Thus, proximity to a plentiful supply of energy is often a
determining factor in deciding the plant's location. 5) Environmental Concerns Most importantly,
however, concerns about the environment must be carefully taken into consideration. The
chemical reaction of changing sulfur and other substances to sulfuric acid results in the formation
of other substances like sulfur dioxide. This causes acid rain. Therefore, there is a big problem
about sulfuric plants causing damage to our environment as the plant is a source of sulfur
emission leading to that of acid rain. 6) Water Supplies Still another factor is the closeness of the
location of the plants to water supplies as many manufacturing plants use water for cooling
purposes. In addition to these factors, these questions must also be answered: Is land available
near the proposed site at a reasonable cost? Is the climate of the area suitable? Are the general
living conditions in the area suitable for the people involved who will be relocating in the area? Is
there any suggestions offered by governments to locate in a particular region? The final decision
on where the sulfuric acid plant really involves a careful examination and a compromise among all
of the factors that have been discussed above. Producing Sulfuric Acid Sulfuric acid is produced
by two principal processes-the chamber process and the contact process. The contact process is
the current process being used to produce sulfuric acid. In the contact process, a purified dry gas
mixture containing 7-10% sulfur dioxide and 11-14% oxygen is passed through a preheater to a
steel reactor containing a platinum or vanadium peroxide catalyst. The catalyst promotes the
oxidation of sulfur dioxide to trioxide. This then reacts with water to produce sulfuric acid. In
practice, sulfur trioxide reacts not with pure water but with recycled sulfuric acid.The reactions
are: 2SO2 O2 * 2SO3 SO3 H2O * H2SO4 The product of the contact plants is 98-100%
acid. This can either be diluted to lower concentrations or made stronger with sulfur trioxide to
yield oleums. For the process, the sources of sulfur dioxide may be produced from pure sulfur,
from pyrite, recovered from smelter operations or by oxidation of hydrogen sulfide recovered
from the purification of water gas, refinery gas, natural gas and other fuels. Battery Acid Industry
Many industries depend on sulfuric acid. Among these industries is the battery acid industry. The
electric battery or cell produces power by means of a chemical reaction. A battery can be primary
or secondary. All batteries, primary or secondary, work as a result of a chemical reaction. This
reaction produces an electric current because the atoms of which chemical elements are made, are
held together by electrical forces when they react to form compounds. A battery cell consists of
three basic parts; a positively charged electrode, called the cathode, a negatively charged
electrode, called the anode, and a chemical substance, called an electrolyte, in which the
electrodes are immersed. In either a wet or dry cell, sufficient liquid must be present to allow the
chemical reactions to take place. Electricity is generated in cells because when any of these
chemical substances is dissolved in water , its molecules break up and become electrically charged
ions. Sulfuric acid is a good example. Sulfuric acid, H2SO4, has molecules of which consist of
two atoms of hydrogen, one of sulfur and four oxygen. When dissolved in water, the molecules
split into three parts, the two atoms of hydrogen separate and in the process each loses an
electron, becoming a positively charged ion (H ). The sulfur atom and the four atoms of oxygen
remain together as a sulfate group (SO4), and acquire the two electrons lost by the hydrogen
atoms, thus becoming negatively charged (SO4--). These groups can combine with others of
opposite charge to form other compounds. The lead-acid cell uses sulfuric acid as the electrolyte.
The lead-acid storage battery is the most common secondary battery used today, and is typical of
those used in automobiles. The following will describe both the charging and discharging phase of
the lead-storage battery and how sulfuric acid, as the electrolyte, is used in the process. The lead
storage battery consists of two electrodes or plates, which are made of lead and lead peroxide and
are immersed in an electrolytic solution of sulfuric acid. The lead is the anode and the lead
peroxide is the cathode. When the battery is used, both electrodes are converted to lead sulfate by
the following process. At the sulfate ion that is present in the solution from the sulfuric acid. At
the cathode, meanwhile, the lead peroxide accepts two electrons and releases the oxygen; lead
oxide is formed first, and then lead joins the sulfate ion to form lead sulfate. At the same time,
four hydrogen ions released from the acid join the oxygen released from the lead peroxide to form
water. When all the sulfuric acid is used up, the battery is "discharged" produces no current. The
battery can be recharged by passing the current through it in the opposite direction. This process
reverses all the previous reactions and forms lead at the anode and lead peroxide at the cathode.
Proposed Problem i) The concentration of sulfuric acid is 0.0443 mol/L. The pH is: No. mol of
hydrogen ions = 0.0443 mol/L x 2 = 0.0886 mol/L hydrogen ions pH = - log [H] = - log (0.0886)
= - (-1.0525) = 1.05 Therefore, pH is 1.05. ii) The amount of base needed to neutralize the lake
water is: volume of lake = 2000m x 800m x 50m = 800,000,000 m3 or 8x108 m3 since
1m3=1000L, therefore 8x1011 L 0.0443 mol/L x 8x1011 = 3.54 x 1010 mol of H2SO4 in water #
mol NaOH = 3.54 x 1010 mol H2SO4 x 2 mol NaOH 1 mol H2SO4 = 7.08 x 1010 mol of NaOH
needed Mass of NaOH = 7.08 x 1010 mol NaOH x 40 g NaOH 1 mol NaOH = 2.83 x 1012 g
NaOH or 2.83 x 109 kg NaOH Therefore a total of 2.83 x 1012 g of NaOH is needed to
neutralize the lake water. iii) The use of sodium hydroxide versus limestone to neutralize the lake
water: Sodium hydroxide: Sodium hydroxide produces water when reacting with an acid, it also
dissolves in water quite readily. When using sodium hydroxide to neutralize a lake, there may be
several problems. One problem is that when sodium hydroxide dissolves in water, it gives off heat
and this may harm aquatic living organisms. Besides this, vast amounts of sodium hydroxide is
required to neutralize a lake therefore large amounts of this substance which is corrosive will have
to be transported. This is a great risk to the environment if a spill was to occur. The following
equation shows that water is produced when using sodium hydroxide. 2NaOH H2SO4 * Na2
SO4 2H2O Limestone: Another way to neutralize a lake is by liming. Liming of lakes must be
done with considerable caution and with an awareness that the aquatic ecosystem will not be
restored to its original pre-acidic state even though the pH of water may have returned to more
normal levels. When limestone dissolves in water it produces carbon dioxide. This could be a
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