WAEC and JAMB Chemistry 13: Chemistry, Industry and the Environment

chemistry

Chemistry, Industry and the Environment

Is chemistry and industry any help to our environment or is it an obstacle?

 

Environmental problems and concerns like climate change, water pollution and renewable energy constantly constitute the headlines of news in radio, television, newspapers, magazines and even online, everywhere. In fact the issue has come to stay as an unavoidable part of our day to day life.

 

A lot of people consider chemistry and the chemical industry as injurious to the environment. Nevertheless, numerous innovative progresses and scientific researches in the area of chemistry are assisting us to build up additional environment friendly materials and applications, whilst safeguarding the worth and the standard of living we look forward to.

 

Down the years, the chemistry and chemical industry and the public at large discovered the dangerous effects of a few chemical practices and how essential it is to ensure the safety of our environment. Previously the awareness regarding the harmful effect of our advanced way of life is very minimal.

 

What was more perceived then is the positive impact of technology and advancement of manufacturing helpful innovative materials and products.

 

Research conducted in the field of biological sciences and chemistry has exposed that industrial procedures in chemistry and petrochemistry could contribute in discovering solutions to environmental problems like the climate change, waste management, recycling, and energy efficiency and so on.

 

If there was nothing like “chemistry”, it would have been very difficult to fully comprehend these environmental problems let alone providing solutions to getting the issues resolved more ways.

 

Nowadays, chemists and petrochemists are conducting research into discovering fresh methods that are more sustainable and environmentally friendly and at the same time preserving the advancement of our economy and our industry. Examples incorporate:

 

• Biofuels: Biofuels is the transportation fuel resulting from biomass. There are many product of biomass like sugar cane, rape seed, corn, straw, wood, animal and agriculture remains and waste product can be changed into fuels for transport;

 

• Bioplastics: This is the process through which plastic materials are produced with the help of natural sources like plants that are biodegradable and which would constitute no environmental hazard;

 

• Insulation: The study of chemistry had made possible improved insulating materials to facilitate higher energy-efficient homes and buildings;

 

• Less heavy plastic composites that have also been made possible through technological advancement help to minimize cars and airplanes propensity to consume fuel;

 

• Fuel cells: Fuel cells are another alternative to fossil fuels. When it is utilized as fuel in cars or motorbikes, the hydrogen fuel cells manufactures water vapour as an alternative for exhaust gases;

 

• New lighting technologies: Technology like Organic Light Emitting Diodes – OLEDS which produce more light with less electricity;

 

• Both Wind turbines and solar paneling: depend on materials manufactured by the chemical industry. The metal blades of wind turbines have to a great extent been replaced by blades that are manufactured with a fibre glass-reinforced polyester to withstand a harsh weather condition.

 

The Society has the tendency of considering every artificial chemical as dreadful and all that is natural as good. The mere fact that something is natural does not automatically mean that it is fine for the health or the environment or hazardous if it’s an artificially made chemical.

 

The burning of wood for an example appears to be natural but the smoke that is given out when a wood is burnt can be detrimental the health and environment just like every other processes of burning.

 

The Extraction of metals

We will only talk about the many factors that determine the choice of method for extracting metals from their ores, like reduction by carbon, reduction by a reactive metal such as sodium or magnesium, and reduction by electrolysis.

 

What are “ores”?

An ore is any natural source of a metal that you can inexpensively extract the metal from.

 

Aluminum, for instance is the most naturally occurring metal on earth. It is found in different kinds of minerals. Nevertheless, it is not cost effective to extract aluminum from the majority of these minerals. As an alternative, the common ore of aluminum is bauxite – which is composed of 50 – 70% of aluminum oxide.

 

Copper is less found in nature but can luckily be extracted from high-grade ores ie ores with a great percentage of copper in certain places. The fact that copper is a valuable metal, necessitates that it is extracted as well from low-grade ores.

 

Ores are mainly

 

1. oxides – for instance:

bauxite Al2O3

haematite Fe2O3

rutile TiO2

 

2. sulphides – for instance:

pyrite FeS2

chalcopyrite CuFeS2

 

Concentrating the ore

Concentrating the ore or making the ore concentrated merely means to get rid of as much of the unnecessary rocky material as possible from the ore before it is transformed into the metal.

 

Occasionally this is carried out chemically. For instance, pure aluminum oxide is extracted from bauxite by a procedure that involves a reaction with sodium hydroxide solution. A number of copper ores can be transformed into copper (II) sulphate solution by allowing the crushed ore in contact with dilute sulphuric acid to stand for a long time. Copper can afterward be extracted from the copper (II) sulphate solution.

 

But, in a lot of instances the metal compound can be separated from not needed rocky material by physical means. An example of this is shown through froth flotation.

 

Reduction of the metal compound to the metal

Why the process is a reduction process.

 

When you are starting compound is an oxide of a metal, the ore is normally being reduced due to the removal of oxygen from it.

 

On the other hand, when your starting material is a sulphide ore, a reduction by the removal of oxygen doesn’t help here. What is more feasible in this situation is a reduction by electron addition.

 

You can consider these ores as possessing positive metal ions. To convert them to the metal, you would require addition of electrons by reduction.

 

Selecting a method of reduction

There are many economic factors you need to consider when deciding a method of reduction to use for a particular type of ore. Some of the factors are:

 

• The cost of the reducing agent;

 

• The cost of energy;

 

• The extent of purity you are requiring in the metal.

 

There might be other environmental factors to also consider.

 

Reduction by Carbon

Carbon (as coke or charcoal) is very cheap. It acts as both the reducing agent and the fuel that makes available the heat for the reduction process.

 

However, in some cases for instance with aluminum the temperature necessary to reduce carbon is very high and is not economically feasible. In this situation, another method of reduction is employed.

 

Carbon might as well be left in the metal as a contamination. Sometimes this can be detached after that for instance in the extraction of iron; sometimes it can’t as an example in the process of producing titanium. As a result another method is employed for such situations.

 

Reduction with the help of a more reactive metal

Titanium is extracted by reducing titanium (IV) chloride with a more reactive metal like sodium or magnesium. This is the only method of obtaining a high purity metal from its ore.

 

The more reactive metal sodium easily gives out electrons when forming its ions. As illustrated in the equation below:

 

These electrons are employed in the reduction of titanium(IV) chloride. The problem with this method of extraction is that is very costly. The more reactive metal is very difficult and expensive to extract. It would necessitate the use of an expensive reducing agent to reduce a metal like titanium for an example.

 

Reduction by electrolysis

Reduction by electrolysis is a popular method of reducing a more reacting metal from their ore for instance Aluminum and all the metals that above it in the homologous series.

 

It is a method of extracting copper and as well for the purification of copper. During the process of the electrolysis, electrons are being deposited directly to the metal ions at the negative electrode or cathode leading to the reduction of the metal ion into a neutal metal atom.

 

The disadvantage of this is the cost of the electricity as in the case of aluminum but the good thing about it is the possibility of obtaining a very pure metal.

 

An alloy

An alloy is a mixture or solid solution of two or more metal. An alloy possesses one or more of three of the following

 

1. solid solution of the elements (a single phase)

 

2.A mixture of metallic phases (two or more solutions)

 

3. An intermetallic compound with no separate boundary between the phases.

 

Solid solution alloys give one solid phase microstructure, whereas partial solutions displays two or more phases that might or might not be homogeneous in supply, consequent on the thermal treatment history of the substance. An inter-metallic compound has another alloy or pure metal implanted inside another pure metal.

 

Alloys are employed in certain applications, where their properties are better than those of the pure constituent elements for a particular application. Examples of alloys are solder:

 

• brass,

• pewter,

• phosphor bronze

• steel

• and an amalgam.

 

Steel for an example is an alloy of iron with carbon and, normally, minute amounts of some other elements, each of which gives a number of exclusive characteristic to steel.

 

Stainless steel alloys are a combination of iron, chromium and nickel commonly customized by the presence of other elements. This family of alloys is for the most part dead set against corrosion, in disparity with the rusting observable fact that destroys normal steel;

 

• Beryllium-copper alloys has more strength and higher electrical conductivity power than the rest alloys of copper;

 

• gallium arsenide is a an extremely conducting alloy used in laser-beam technology;

 

• super alloys of nickel and cobalt are made use of in aircraft engines for the reason that they are corrosion free and heat-resistance;

 

• aluminum with minute quantities of silicon, iron, copper, manganese, magnesium and zinc forms an alloy specially made for the production of beverage cans;

 

Land, Air And Water Pollution

 

What is pollution?

Pollution is the addition of a contaminant into the environment. It is caused mainly by human actions, but can as well a result of natural disasters.

 

Pollution is harmful to the Earth’s environment and things that live on it in various ways.

 

The three main types of pollution are:

 

Land Pollution

Land pollution is contamination of the Earth’s natural land surface by industrial, commercial, domestic and agricultural practices.

 

Sources of land pollution

Some of the key sources of land pollution are:

• Chemical and nuclear plants

• Industries and factories

• Oil refineries

• Human sewage

• Oil and antifreeze leakage from automobiles

• Mining

• Littering around

• Overcrowding of landfills

• Deforestation

• The debris from construction

 

Air Pollution

Air pollution is the building up of harmful materials into the atmosphere that have the tendency of endangering human life and other living things

 

Sources of air pollution

Some air pollution are:

• Emissions by Automobile

• The smoke of Tobacco

• Burning of coal

• Acidic rain

• Noise pollution from cars and production industries, Power plants, building constructions, outsized ships, fumes from paints, sprays of Aerosol, Wildfires and Nuclear weapons

 

Water Pollution

Water pollution is caused by the introduction of chemical, biological and physical materials into large water bodies which reduces the quality of life that lives in the water and lives that makes use of the water for survival.

 

Sources of water pollution:

Some key sources of water pollution are:

• Factories and refineries

• Waste treatment plants and facilities

• Mining

• Pesticides, herbicides and fertilizers that are non-biodegradable

• Human waste

• Oil spills

• Faulty septic systems

• Soap from our washing

• Oil and antifreeze leakage from cars

• Domestic chemicals

• Animal waste