Scope
Green Chemistry provides a unique forum for the publication of innovative
research on the development of alternative sustainable technologies.
The scope of Green Chemistry is based on, but not limited to, the definition
proposed by Anastas and Warner (Green Chemistry: Theory and Practice, P T
Anastas and J C Warner, Oxford University Press, Oxford, 1998). Green chemistry is
the utilisation of a set of principles that reduces or eliminates the use or generation of
hazardous substances in the design, manufacture and application of chemical
products.
Green Chemistry is at the frontiers of this interdisciplinary science and
publishes research that attempts to reduce the environmental impact of the chemical
enterprise by developing a technology base that is inherently non-toxic to living
things and the environment. Submissions on all aspects of research relating to the
endeavor are welcome.
The journal publishes original and significant cutting-edge research that is
likely to be of wide general appeal. Coverageincludes the following, butis not limited
to:
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the application of innovative technology to establish industrial procedures
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the development of environmentally improved routes, synthetic methods and
processes to important products
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the design of new, greener and safer chemicals and materials
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the use of sustainable resources
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the use of biotechnology alternatives to chemistry-based solutions
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methodologies and tools for measuring environmental impact and
application to real world examples
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chemical aspects of renewable energy
reading
Substance structure
Substance
Substance [sub'-stuns] is the material, or matter, of which something is made.
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Substances are physical things that can be seen, touched, or measured. They are made
up of one or more elemental parts. Iron, aluminium, water and air are examples of
substances.
Steam and liquid water are two different forms of the same chemical substance,
water.
The Latin word substantia - a translation of the Greek word for the essence
(ousia), and in Latin to describe the essence of using the word essentia.
Did you know when you are breathing you are actually inhaling elements? The
air you breathe is made up of many elements like oxygen, nitrogen, and argon.
Elements are everywhere. They are the building blocks of everything on Earth: your
dog, the mountains, your car, your eyes, and, yes, even beer. In this lesson, we will
discuss what an element is, how elements are written as symbols, and how they are
the building blocks of all matter.
Substances
Substances are distinguished by their properties – colour, smell, taste, specific
gravity, greater or lesser hardness, melting and boiling points, volatility, etc.
For example, in describing the properties of sugar, one can state that sugar is a
hard, brittle substance, white in colour, sweet to the taste, without odour, easily
soluble in water, heavier than water and it turns brown when it is heated, etc.
In order to learn the properties of a substance one must have it in its pure form.
Even small admixtures of foreign substances may change the properties of a
substance. For example: pure water is both colourless and transparent, but if a drop of
milk is added to a glass of water, the water becomes clouded; if a drop of ink is
added, the water becomes coloured. All the enumerated properties are not those of
water but they are the properties of the admixtures.
In some cases, one may see at once that a substance is heterogeneous, that is, a
mixture of different substances.
Granite, cement, petroleum are examples of non-homogeneous materials; they
consist of mixtures of substances. Thus, granite is a mixture of varying quantities of
silica, feldspar, and mica, each of which possesses its own set of properties. Coal is
not a substances too because different samples contain different relatives amounts of
ash, water, carbon, and other components.
Every materials, therefore, consists of a single (pure) substance, or it is a
mixture of two or more substances, each of which retains in the mixture its own
characteristic properties.
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Atomic structure
What Is an Element?
An element is a pure substance that cannot be broken down by chemical
methods into simpler components. For example, the element gold cannot be broken
down into anything other than gold. If you kept hitting gold with a hammer, the
pieces would get smaller, but each piece will always be gold. You can think of each
kind of element having its own unique fingerprint making it different than other
elements. Elements consist of only one type of atom. An atom is the smallest particle
of an element that still has the same properties of that element. All atoms of a specific
element have exactly the same chemical makeup, size, and mass. There are a total of
118 elements, with the most abundant elements on Earth being helium and hydrogen.
Many elements occur naturally on Earth; however, some are created in a laboratory
by scientists by nuclear processes. Elements Are Written as Symbols Instead of
writing the whole elemental name, elements are often written as a symbol. For
example, O is the symbol for oxygen, C is the symbol for carbon, and H is the
symbol for hydrogen. Not all elements have just one letter as the symbol, but have
two letters - like Al is the symbol for aluminum and Ni is the symbol for nickel. The
first letter is always capitalized, but the second letter is not. Symbol names do not
always match the letters in the elemental name. For example, Fe is the symbol for
iron and Au is the symbol for gold. These symbol names are derived from the Latin
names for those elements.
Radioactivity. Nuclear reactions
Radioactivity was discovered in 1896 by the French scientist Henri Becquerel,
while working with phosphorescent materials. These materials glow in the dark after
exposure to light, and he suspected that the glow produced in cathode ray tubes by X-
rays might be associated with phosphorescence. He wrapped a photographic plate in
black paper and placed various phosphorescent salts on it. All results were negative
until he used uranium salts. The uranium salts caused a blackening of the plate in
spite of the plate being wrapped in black paper. These radiations were given the name
"Becquerel Rays".
It soon became clear that the blackening of the plate had nothing to do with
phosphorescence, as the blackening was also produced by non-phosphorescent salts
of uranium and metallic uranium. It became clear from these experiments that there
was a form of invisible radiation that could pass through paper and was causing the
plate to react as if exposed to light.
At first, it seemed as though the new radiation was similar, then recently
discovered X-rays. Further research by Becquerel, Ernest Rutherford, Paul Villard,
Pierre Curie, Marie Curie, and others showed that this form of radioactivity was
significantly more complicated. Rutherford was the first to realize that all such
elements decay in accordance with the same mathematical exponential formula.
Rutherford and his student Frederick Soddy were the first to realize that many decay
processes resulted in the transmutation of one element to another. Subsequently, the
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radioactive displacement law of Fajans and Soddy was formulated to describe the
products of alpha and beta decay.
The early researchers also discovered that many other chemical elements,
besides uranium, have radioactive isotopes. A systematic search for the total
radioactivity in uranium ores also guided Pierre and Marie Curie to isolate two new
elements: polonium and radium. Except for the radioactivity of radium, the chemical
similarity of radium to bariummade these two elements difficult to distinguish.
Marie and Pierre Curie’s study of radioactivity is an important factor in science
and medicine. After their research on Becquerel's rays led them to the discovery on
both radium and polonium, they coined the term "radioactivity." Their research on the
penetrating rays in uranium and discovery of radium launched an era of using radium
for treatment of cancer. Their exploration of radium could be seen as the first
peaceful use of nuclear energy and the start of modern nuclear medicine.
A nuclear reaction is considered to be the process in which two nuclear
particles (two nuclei or a nucleus and a nucleon) interact to produce two or more
nuclear particles or X-rays (gamma rays). Thus, a nuclear reaction must cause a
transformation of at least one nuclide to another. Sometimes if a nucleus interacts
with another nucleus or particle without changing the nature of any nuclide, the
process is referred to a nuclear scattering, rather than a nuclear reaction. Perhaps the
most notable nuclear reactions are the nuclear fusion reactions of light elements that
power the energy production of stars and the Sun. Natural nuclear reactions occur
also in the interaction between cosmic rays and matter.
The most notable man-controlled nuclear reaction is the fission reaction which
occurs in nuclear reactors. Nuclear reactors are devices to initiate and control a
nuclear chain reaction, but there are not only manmade devices. The world’s first
nuclear reactor operated about two billion years ago. The natural nuclear reactor
formed at Oklo in Gabon, Africa, when a uranium-rich mineral deposit became
flooded with groundwater that acted as a neutron moderator, and a nuclear chain
reaction started. These fission reactions were sustained for hundreds of thousands of
years, until a chain reaction could no longer be supported. This was confirmed by
existence of isotopes of the fission-product gas xenon and by different ratio of U-
235/U-238 (enrichment of natural uranium).
Natural
resources and
power
Natural
resources
Natural resources are resources that exist without the actions of humankind.
This includes all valued characteristics such as magnetic, gravitational, and electrical
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properties and forces. On earth we include sunlight, atmosphere, water, land, air
(includes all minerals) along with all vegetation and animal life that naturally subsists
upon or within therefore identified characteristics and substances.
Natural resources may be further classified in different ways. Natural resources
are materials and components (something that can be used) that can be found within
the environment. Every man-made product is composed of natural resources (at its
fundamental level). A natural resource may exist as a separate entity such as fresh
water, and air, as well as a living organism such as a fish, or it may exist in an
alternate form which must be processed to obtain the resource such as metal ores,
mineral oil, and most forms of energy.
There is much debate worldwide over natural resource allocations; this is
particularly true during periods of increasing scarcity and shortages (depletion and
overconsumption of resources) but also because the exportation of natural resources
is the basis for many economies (particularly for developed countries).
Some natural resources such as sunlight and air can be found everywhere, and
are known as ubiquitous resources. However, most resources only occur in small
sporadic areas, and are referred to as localized resources. There are very few
resources that are considered inexhaustible (will not run out in foreseeable future) –
these are solar radiation, geothermal energy, and air (though access to clean air may
not be). The vast majority of resources are theoretically exhaustible, which means
they have a finite quantity and can be depleted if managed improperly.
In recent years, the depletion of natural resources has become a major focus of
governments and organizations such as the United Nations. This is evident in the
UN's Agenda 21 Section Two, which outlines the necessary steps to be taken by
countries to sustain their natural resources. The depletion of natural resources is
considered to be a sustainable development issue. The term sustainable development
has many interpretations, most notably the Brundtland Commission's 'to ensure that it
meets the needs of the present without compromising the ability of future generations
to meet their own needs', however in broad terms it is balancing the needs of the
planet's people and species now and in the future. In regards to natural resources,
depletion is of concern for sustainable development as it has the ability to degrade
current environments and potential to impact the needs of future generations.
The conservation of natural resources is the fundamental problem. Unless we
solve that problem, it will avail us little to solve all others.
Natural resources can be consumed directly or indirectly. For instance, humans
depend directly on forests for food, biomass, health, recreation and increased living
comfort. Indirectly forests act as climate control, flood control, storm protection and
nutrient cycling.
Raw materials
Sometimes, natural resources can be used as raw materials to produce
something. For instance, we can use a tree from the forest to produce timber. The
timber is then used to produce wood for furniture or pulp for paper and paper
products. In this scenario, the tree is the raw material.
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Every item in your home was made from a raw material that came from a
natural resource. The tea mug, electricity at home, bread, clothes, you name them:
each of them came from a natural resource.
Natural resources come in many forms. It may be a solid, liquid or gas. It may
also be organic or inorganic. It may also be metallic or non-metallic. It may be
renewable or non-renewable.
Renewable and Non-renewable Resources
All natural resources fall under two main categories: renewable and non-
renewable resources. The table below will help us understand this better.
Renewable resources
Renewable resources are those that are constantly available (like water) or can
be reasonably replaced or recovered, like vegetative lands. Animals are also
renewable because with a bit of care, they can reproduce off springs to replace adult
animals. Even though some renewable resources can be replaced, they may take
many years and that does not make them renewable.
If renewable resources come from living things, (such as trees and animals)
they can be called organic renewable resources.
If renewable resources come from non-living things, (such as water, sun and
wind) they can be called inorganic renewable resources.
Non-renewable resources
Non-renewable resources are those that cannot easily be replaced once they are
destroyed. Examples include fossil fuels. Minerals are also non-renewable because
even though they form naturally in a process called the rock cycle, it can take
thousands of years, making it non-renewable. Some animals can also be considered
non-renewable, because if people hunt for a particular species without ensuring their
reproduction, they will be extinct. This is why we must ensure that we protect
resources that are endangered.
Non-renewable resources can be called inorganic resources if they come from
non-living things. Examples include include, minerals, wind, land, soil and rocks.
Some non-renewable resources come from living things — such as fossil fuels.
They can be called organic non-renewable resources.
Metallic and Non-metallic Resources
Inorganic resources may be metallic or non-metallic. Metallic minerals are
those that have metals in them. They are harder, shiny, and can be melted to form
new products. Examples are iron, copper and tin. Non-metallic minerals have no
metals in them. They are softer and do not shine. Examples include clay and coal.
Why are Natural Resources so important?
Natural resources are available to sustain the very complex interaction between
living things and non-living things. Humans also benefit immensely from this
interaction. All over the world, people consume resources directly or indirectly.
Developed countries consume resources more than under-developed countries.
In what form do people consume natural resources? The three major forms
include
food and drink, housing and infrastructure, and mobility. These three make up
more than 60% of resource use.
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Natural Resource
Products or Services
Air
Wind energy, tires
Animals
Foods (milk, cheese, steak, bacon) and clothing (wool
sweaters, silk shirts, leather belts)
Coal
Electricity
Minerals
Coins, wire, steel, aluminum cans, jewelry
Natural gas
Electricity, heating
Oil
Electricity, fuel for cars and airplanes, plastic
Plants
Wood, paper, cotton clothing, fruits, vegetables
Sunlight
Solar power, photosynthesis
Water
Hydroelectric energy, drinking, cleaning
Power resources
Since 1933 the World Energy Council has published a report presenting
statistics for reserves, and production of various resources at the global level. The
World Energy Resources study group and its working groups collect and evaluate
data on resources. It focuses on proven reserves, examines the evolving nature of the
energy mix in countries worldwide and highlights emerging energy sources and
technologies.
The World Energy Resources report is a strategic publication of the World
Energy Council prepared triennially and timed for release at each World Energy
Congress. It offers a uniquely global perspective on twelve major resources. This
highly regarded publication is an essential tool for governments, industry, investors,
NGOs and academia.
As energy is the main ‘fuel’ for social and economic development, and since
energy-related activities have significant environmental impacts, it is important for
decision-makers to have access to reliable and accurate data in a user-friendly format.
The World Energy Council has for decades been a pioneer in the field of energy
resources and every three years publishes its World Energy Resources report (WER)
[formerly Survey of Energy Resources (SER)], which is released during the World
Energy Congress.
The energy sector has long lead times and therefore any long-term strategy
should be based on sound information and data. Detailed resource data, selected cost
data and a technology overview in the main WER report provide an excellent
foundation for assessing different energy options based on factual information
supplied by the WEC members from all over the world.
The work is divided into twelve resource-specific work groups, called
Knowledge Networks; complemented by a further three groups investigating the
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cross-cutting issues of, carbon capture and storage, energy efficiency and energy
storage. These Knowledge Networks provide updated data for the website and
publications, as well as working on timely deep-dives with a resource focus.
An example of a magnetic force is the pull that attracts metals to the magnet.
Now, the electrical field induced causes waves, called electromagnetic waves, and
they can travel through a vacuum (air), particles or solids. These waves resemble the
ripple (mechanical) waves you see when you drop a rock into a swimming pool, but
with electromagnetic waves, you do not see them, but you often can see the effect of
it. The energy in the electromagnetic waves is what we call radiant energy. There are
different kinds of electromagnetic waves and all of them have different wavelengths,
properties, frequencies and power, and all interact with matter differently. The entire
wave system from the lowest frequency to the highest frequency is known as the
electromagnetic spectrum. The shorter the wavelength, the higher its frequency and
vice versa. White light, for example, is a form of radiant energy, and its frequency
forms a tiny bit of the entire electromagnetic spectrum. What is radiant energy?
When radiant energy comes into contact with matter, it changes the properties
of that matter. For example, when micro-waves (which form part of the entire
spectrum) are set off in a microwave oven, the water molecules in the food are
charged and caused to vibrate billions of times per second, generating heat, that
causes the food to cook. The microwave oven works with the concept of radiant
energy (electromagnetic waves).
Energy Stored
Energy cannot be created or destroyed, but it can be saved in various forms.
One way to store it is in the form of chemical energy in a battery. When connected in
a circuit, energy stored in the battery is released to produce electricity.
Energy Stored
If you look at a battery, it will have two ends: a positive terminal and a
negative terminal. If you connect the two terminals with wire, a circuit is formed.
Electrons will flow through the wire and a current of electricity is produced. Energy
can also be stored in many other ways. Batteries, gasoline, natural gas, food, water
towers, a wound up alarm clock, a Thermos flask with hot water and even pooh are
all stores of energy. They can be transferred into other kinds of energy.
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