CHEMENG - MIDTERM EXAM REVIEWER

Alpha Particle Emission

which is an ordinary helium nucleus, or is given off. Alpha decay can most simply be described like this: The nucleus of an atom splits into two parts.  One of these parts (the alpha particle) goes zooming off into space. The nucleus left behind has its atomic number reduced by 2 and its mass number reduced by 4 (that is, by 2 protons and 2 neutrons). 

Beta Particle Emission

which produces an electron. Beta decay is somewhat more complex than alpha decay is. These points present a simplified view of what beta decay actually is: A neutron inside the nucleus of an atom breaks down, changing into a proton. It emits an electron and an anti-neutrino, which go zooming off into space. The atomic number goes UP by one and mass number remains unchanged.

Gamma Radiation

Which consist of high-energy photons. Because gamma emission changes neither the mass number nor the atomic number, it is ordinarily omitted in writing nuclear equations. Gamma rays, because of their size, have the lowest ionizing power.

Positron Emission

is identical to an electron except that it has a charge of +1 rather than -1. 

K-Electron Capture

in which an electron in the innermost energy level falls into the nucleus. The result of K-electron capture is the same as positron emission where the mass number remains unchanged, and whereas atomic number is decreased by one unit. Electron capture is not like any other decay - alpha, beta, or positron. All other decays shoot something out of the nucleus. In electron capture, something ENTERS the nucleus. These points present a simplified view of what electron capture is: An electron from the closest energy level falls into the nucleus, which causes a proton to become a neutron. A neutrino is emitted from the nucleus. Another electron falls into the empty energy level and so on causing a cascade of electrons falling. One free electron, moving about in space, falls into the outermost empty level.  The atomic number goes DOWN by one and mass number remains unchanged.

Joule

is a unit of energy in the SI system. Energy is measured in joules. However, joules are very large units while dealing with electrons and other tiny particles. Hence, an electron volt is used while dealing with smaller particles like electrons.

Electron Volt

is defined as the amount of energy one electron gains by moving through a potential difference of one volt. Hence, one electron volt is equal to elementary charge (1.60217657× 10^-19 coulombs (C)) multiplied by one volt.

Mass Defect

refers to the difference in mass between an atom and the sum of the masses of the protons,  neutrons, and electrons of the atom.

Binding Energy

of a nucleus is, in a sense, a measure of stability. The greater the binding energy, the more difficult it would be to decompose the nucleus into protons and neutrons.

Fission

is the splitting of an atomic nucleus into two or more lighter nuclei accompanied by energy release. The original heavy atom is termed the parent nucleus and the lighter nuclei are daughter nuclei. 

Fusion

joins atomic nuclei together. The element formed has more neutrons or more protons than that of the starting material. For example, hydrogen and hydrogen can fuse to form helium.

Fuels

are substances which undergo combustion in the presence of air to produce a large amount of heat that can be used economically for domestic and industrial purposes. This definition does not include nuclear fuel.

Wood or Sticks

The first known use of fuel was the combustion  by Homo erectus nearly two million years ago. Throughout most of human history only fuels derived from plants or animal fat were used by humans.

Charcoal

a wood derivative, has been used since at least 6,000 BCE for melting metals. It was only supplanted by coke, derived from coal, as European forests started to become depleted around the 18th century. Charcoal briquettes are now commonly used as a fuel for barbecue cooking. Is a lightweight black carbon residue produced by removing water and other volatile constituents from animal and plant materials. Charcoal is usually produced by slow pyrolysis. The heating of wood or other organic materials in the absence of oxygen, this process is called Charcoal Burning. The finished charcoal consists largely of carbon. The advantage of burning charcoal compared to burning wood is the absence of water and other components. This allows charcoal to burn at higher temperatures, and give off very little smoke; wood can release a significant amount of steam, organic volatiles, and unburnt carbon particles—soot—in its smoke, when it is not burned completely.

Coke

is a grey, hard, and porous fuel with a high carbon content and few impurities, made by heating coal or oil in the absence of air—a destructive distillation process. It is an important industrial product, used mainly in iron ore smelting, but also as a fuel in stoves and forges when air pollution is a concern. The unqualified term "coke" usually refers to the product derived from low-ash and low-sulphur bituminous coal by a process called coking. A similar product called petroleum coke, or pet coke, is obtained from crude oil in oil refineries. Coke may also be formed naturally by geologic processes.

Crude Oil

It consists of naturally occurring hydrocarbons of various molecular weights and may contain miscellaneous organic compounds.The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. It  was distilled by Persian chemists, with clear descriptions given in Arabic handbooks such as those of Muhammad ibn Zakarīya Rāzi. He described the process of distilling crude oil/petroleum into kerosene, as well as other hydrocarbon compounds, in his Kitab alAsrar (Book of Secrets). Kerosene was also produced during the same period from oil shale and bitumen by heating the rock to extract the oil, which was then distilled. Rāzi also gave the first description of a kerosene lamp using crude mineral oil, referring to it as the "naffatah".

Petroleum

is a naturally occurring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column.

Fossil Fuel

petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure. Were rapidly adopted during the Industrial Revolution, because they were more concentrated and flexible than traditional energy sources, such as water power. They have become a pivotal part of our contemporary society, with most countries in the world burning fossil fuels in order to produce power. Currently the trend has been towards renewable fuels, such as biofuels like alcohols.

Kerosene

also known as paraffin, lamp oil, and coal oil (an obsolete term), is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from Greek: κηρός (keros) meaning "wax", and was registered as a trademark by Canadian geologist and inventor Abraham Gesner in 1854 before evolving into a genericized trademark.

Kerosene Lamp

(also known as a paraffin lamp in some countries) is a type of lighting device that uses kerosene as a fuel.

Tar

is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. Mineral products resembling tar can be produced from fossil hydrocarbons, such as petroleum. Coal tar is produced from coal as a byproduct of coke production. The streets of Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region. In the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan. These fields were described by the Arab geographer Abu al-Hasan 'Alī al-Mas'ūdī in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads.

Peat

also known as turf (/tɜːrf/), is an accumulation of partially decayed vegetation or organic matter.

Primary Fuels

or primary energy sources are dense sources of primary energy found as natural resources. Primary fuels are fuels that are found in nature and can be extracted, captured, cleaned, or graded without any sort of energy conversion or transformation process.

Secondary Fuels

are fuels that are derived from some primary fuel or fuels through chemical or physical processes. The energy for these secondary fuels comes initially from primary energy sources. Gasoline is the best example of a secondary fuel, as it must be made from oil through distillation processes.

Solid Fuels

refers to various forms of solid material that can be burnt to release energy, providing heat and light through the process of combustion. Solid fuels can be contrasted with liquid fuels and gaseous fuels. Common examples of solid fuels include wood, charcoal, peat, coal, Hexamine fuel tablets, wood pellets, corn, wheat, rye, and other grains. Solid fuels are extensively used in rocketry as solid propellants.

Liquid Fuels

are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from fossil fuels; however, there are several types, such as hydrogen fuel (for automotive uses), ethanol, and biodiesel, which are also categorized as a liquid fuel. Many liquid fuels play a primary role in transportation and the economy.

Gaseous Fuels

are hydrocarbons, hydrogen and carbon monoxide mixtures present in gaseous state which forms the basis of potential heat energy or light energy that can be readily disseminated by means of pipes from the origin to the place of consumption. It may be divided into four classes: Natural, Producer, Water and Coal Gasses.

Combustion

is a process in which oxygen from the air reacts with elements or compounds to give heat. During the process of Combustion, C and H of the fuel combine with oxygen of air to form CO2 and H2O respectively. Since the heat content of combustion products, CO2, H2O, etc, being lower than that of reactants (C, H, etc, of fuel), the chemical fuel releases heat during their combustion process.