Course Content
Introduction to Environmental Chemistry
Environmental chemistry is the study of the chemical and biochemical phenomena that occur in nature. It involves the understanding of how the uncontaminated environment works, and which naturally occurring chemicals are present, in what concentrations and with what effects. Environmental chemistry; is the study of sources, reactions, transport, effects and fate of chemical species in water, soil and air environment as well as their effects on human health and natural environment
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Origin of the solar System
Cosmology; is the branch of astronomy involving the study of the of the universe and the solar system. Cosmo-chemistry ;( chemical cosmology); is the study of chemical composition of the matter in the universe and the process that led to those compositions The solar system is made up of the sun (a star) with nine planets orbiting around it. These planets together with all the other heavenly bodies moving around or between individual planet form members of the solar system. Other heavenly body include; asteroids, comets, meteors, meteorites and satellites such as moon. The solar system does not include other stars .
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Solutions
Solutions are defined as homogeneous mixtures that are mixed so thoroughly that neither component can be observed independently of the other. The major component of the solution is called solvent, and the minor component(s) are called solute.
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Chemical Equilibria
Chemical equilibrium in the environment refers to the state where the rates of forward and reverse reactions of a chemical reaction reach a balance. In this state, the concentrations of reactants and products remain constant over time, although the reactions continue to occur.
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Phase Interactions
Phase interactions in solutions refer to the behavior and changes that occur when two or more substances (solutes and solvents) mix together to form a homogeneous mixture. These interactions are related to the different phases of matter, such as solids, liquids, and gases, and how they interact and transform during the process of solution formation.
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Colligative Properties of Solutions
COLLIGATIVE PROPERTIES OF SOLUTIONS Colligative properties are physical properties of solutions that depend on the concentration of solute particles, rather than the specific identity of the solute. The four colligative properties that can be exhibited by a solution are: 1.Boiling point elevation 2.Freezing point depression 3.Relative lowering of vapour pressure 4.Osmotic pressure
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Introduction To Organic Chemistry
Organic chemistry is the study of carbon containing compounds and their properties. This includes the great majority of chemical compounds on the planet, but some substances such as carbonates and oxides of carbon are considered to be inorganic substances even though they contain carbon.
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Air Quality and Pollution
Air Quality and Pollution
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Introduction To Environmental Chemistry
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The Carbon Cycle

Carbon is the second most abundant element in organisms, by mass. Carbon is present in all organic molecules (and some molecules that are not organic such as CO2), and its role in the structure of biomolecules is of primary importance.

Carbon compounds contain energy, and many of these compounds from dead plants and algae have fossilized over millions of years and are known as fossil fuels. Since the 1800s, the use of fossil fuels has accelerated.

Since the beginning of the Industrial Revolution the demand for Earth’s limited fossil fuel supplies has risen, causing the amount of carbon dioxide in our atmosphere to drastically increase.  This increase in carbon dioxide is associated with climate change and is a major environmental concern worldwide.

The carbon cycle is most easily studied as two interconnected subcycles: one dealing with rapid carbon exchange among living organisms and the other dealing with the long-term cycling of carbon through geologic processes.

Figure 2. Carbon dioxide gas exists in the atmosphere and is dissolved in water. Photosynthesis converts carbon dioxide gas to organic carbon, and respiration cycles the organic carbon back into carbon dioxide gas. Long-term storage of organic carbon occurs when matter from living organisms is buried deep underground and becomes fossilized. Volcanic activity and, more recently, human emissions bring this stored carbon back into the carbon cycle.

The Biological Carbon Cycle

Organisms are connected in many ways, even among different ecosystems. A good example of this connection is the exchange of carbon between heterotrophs and autotrophs by way of atmospheric carbon dioxide. Carbon dioxide (CO2) is the basic building block that autotrophs use to build high-energy compounds such as glucose. The energy harnessed from the Sun is used by these organisms to form the covalent bonds that link carbon atoms together.

These chemical bonds store this energy for later use in the process of respiration. Most terrestrial autotrophs obtain their carbon dioxide directly from the atmosphere, while marine autotrophs acquire it in the dissolved form (bicarbonate, HCO3).

Carbon is passed from producers to higher trophic levels through consumption. For example, when a cow (primary consumer) eats grass (producer), it obtains some of the organic molecules originally made by the plant’s photosynthesis.  Those organic compounds can then be passed to higher trophic levels, such as humans, when we eat the cow.  

At each level, however, organisms are performing respiration, a process in which organic molecules are broken  down to release energy. As these organic molecules are broken down, carbon is removed from food molecules to form CO2, a gas that enters the atmosphere.

Thus, CO2 is a byproduct of respiration.  Recall that CO2 is consumed by producers during photosynthesis to make organic molecules. As these molecules are broken down during respiration, the carbon once again enters the atmosphere as CO2.

 Carbon exchange like this potentially connects all organisms on Earth. Think about this: the carbon in your DNA was once part of plant; millions of years ago perhaps it was part of dinosaur.

The Biogeochemical Carbon Cycle

The movement of carbon through land, water, and air is complex, and, in many cases, it occurs much more slowly than the movement between organisms. Carbon is stored for long periods in what are known as carbon reservoirs, which include the atmosphere, bodies of liquid water (mostly oceans), ocean sediment, soil, rocks (including fossil fuels), and Earth’s interior.

As stated, the atmosphere is a major reservoir of carbon in the form of carbon dioxide that is essential to the process of photosynthesis. The level of carbon dioxide in the atmosphere is greatly influenced by the reservoir of carbon in the oceans. The exchange of carbon between the atmosphere and water reservoirs influences how much carbon is found in each.

Carbon dioxide (CO2) from the atmosphere dissolves in water and reacts with water molecules to form ionic compounds. Some of these ions combine with calcium ions in the seawater to form calcium carbonate (CaCO3), a major component of the shells of marine organisms.

These organisms eventually die and their shells form sediments on the ocean floor. Over geologic time, the calcium carbonate forms limestone, which comprises the largest carbon reservoir on Earth.

On land, carbon is stored in soil as organic carbon as a result of the decomposition of organisms or from weathering of terrestrial rock and minerals (the world’s soils hold significantly more carbon than the atmosphere, for comparison).

 Deeper underground are fossil fuels, the anaerobically decomposed remains of plants  and algae that lived millions of years ago. Fossil fuels are considered a non-renewable resource because their use far exceeds their rate of formation.

non-renewable resource is either regenerated very slowly or not at all. Another way for carbon to enter the atmosphere is from land (including land beneath the surface of the ocean) by the eruption of volcanoes and other geothermal systems.

Carbon sediments from the ocean floor are taken deep within Earth by the process of subduction: the movement of one tectonic plate beneath another. Carbon is released as carbon dioxide when a volcano erupts or from volcanic hydrothermal vents.

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