SCIENCE BLOG 1: Hydrocarbon molecules are organic compounds consisting of carbon and hydrogen atoms. In petroleum crude oil, for example, these molecules may include from one to 60 or more carbon atoms. The properties of hydrocarbons depend on the number and arrangement of the carbon and hydrogen atoms in the molecules. The simplest hydrocarbon molecule is methane, with one carbon atom linked to four hydrogen atoms. All other variations of hydrocarbons evolve from this molecule.
Hydrocarbons containing up to four carbon atoms are usually gases at normal ambient temperatures and atmospheric pressure, those with five to 19 carbon atoms are usually liquids, and those with 20 or more are typically solids or semi-solids. The petroleum refining process uses chemicals, catalysts, heat, and pressure to separate and combine the basic types of hydrocarbon molecules naturally found in crude oil into groups of similar molecules. The refining process also rearranges their structures and bonding patterns into different hydrocarbon molecules and compounds.
Naturally occurring hydrocarbon compounds Paraffins The paraffinic series of hydrocarbon compounds have the general formula CnH2n+2 and can be either straight chains (normal) or branched chains (isomers) of carbon atoms (Figure 1). Paraffinic hydrocarbons are very commonly referred to as alkanes. The lighter, straight-chain paraffin molecules are found in natural gas as well as in petroleum refinery byproduct gases and low boiling point liquids. Examples of straight-chain molecules are methane, ethane, propane, and butane (gases containing from one to four carbon atoms), and pentane and hexane (liquids with five to six carbon atoms).
The branched-chain (isomer) paraffins are usually found in heavier fractions of crude oil and have higher octane numbers than normal paraffins. These compounds are saturated hydrocarbons, with all carbon bonds satisfied, that ;is, the hydrocarbon chain carries the full complement of hydrogen atoms.
Aromatics Aromatics are unsaturated ring-type (cyclic) compounds which react readily because they have carbon atoms that are deficient in hydrogen. All aromatics have at least one benzene ring (a single-ring compound characterized by three double bonds alternating with three single bonds between six carbon atoms) as part of their molecular structure (Figure 2). Naphthalenes are fused double-ring aromatic compounds. The most complex aromatics are the polycyclic aromatic hydrocarbons (PAH), also referred to as polynuclear hydrocarbons, with three or more fused aromatic rings and they typically are found in the heavier fractions of petroleum crude oil.
Naphthenes Naphthenes are saturated hydrocarbon compounds having the general formula of CnH2n, arranged in the form of closed rings (cyclic) and found in all fractions of petroleum crude oil except the very lightest. Naphthenes are also commonly referred to as cycloparaffins or cycloalkanes. Some examples of typical naphthenes are depicted in the adjacent Figure 3. Single-ring naphthenes (monocycloparaffins) with five and six carbon atoms predominate, with two-ring naphthenes (dicycloparaffins) found in the heavier ends of the naphtha fraction of petroleum crude oil. Other hydrocarbons Alkenes Alkenes are mono-olefins with the general formula CnH2n and contain only one carbon-carbon double bond in the chain (Figure 4). The simplest alkene is ethylene, with two carbon atoms joined by a double bond and four hydrogen atoms. Olefins are usually formed by thermal and catalytic cracking and rarely occur naturally in unprocessed crude oil. Dienes and alkynes Dienes, also known as diolefins, have two carbon-carbon double bonds (Figure 5). The alkynes, another class of unsaturated hydrocarbons, have a carbon-carbon triple bond within the molecule. Both these series of hydrocarbons have the general formula CnH2n-2. Diolefins such as 1,2-butadiene and 1,3-butadiene, and alkynes such as acetylene, occur in C5 and lighter fractions from cracking. The olefins, diolefins, and alkynes are said to be unsaturated because they contain less than the amount of hydrogen necessary to saturate all the valences of the carbon atoms. These compounds are more reactive than paraffins or naphthenes and readily combine with other elements such as hydrogen, chlorine, and bromine. SCIENCE BLOG 2: Global Warming is caused by many things. The causes are split up into two groups, man-made or anthropogenic causes, and natural causes. Natural Causes Natural causes are causes created by nature. One natural cause is a release of methane gas from arctic tundra and wetlands. Methane is a greenhouse gas. A greenhouse gas is a gas that traps heat in the earth's atmosphere. Another natural cause is that the earth goes through a cycle of climate change. This climate change usually lasts about 40,000 years. Man-made Causes Man-made causes probably do the most damage. There are many man-made causes. Pollution is one of the biggest man-made problems. Pollution comes in many shapes and sizes. Burning fossil fuels is one thing that causes pollution. Fossil fuels are fuels made of organic matter such as coal, or oil. When fossil fuels are burned they give off a green house gas called CO2. Also mining coal and oil allows methane to escape. How does it escape? Methane is naturally in the ground. When coal or oil is mined you have to dig up the earth a little. When you dig up the fossil fuels you dig up the methane as well. Another major man-made cause of Global Warming is population. More people means more food, and more methods of transportation, right? That means more methane because there will be more burning of fossil fuels, and more agriculture. Now your probably thinking, "Wait a minute, you said agriculture is going to be damaged by Global Warming, but now you're saying agriculture is going to help cause Global Warming?" Well, have you ever been in a barn filled with animals and you smell something terrible? You're smelling methane. Another source of methane is manure. Because more food is needed we have to raise food. Animals like cows are a source of food which means more manure and methane. Another problem with the increasing population is transportation. More people means more cars, and more cars means more pollution. Also, many people have more than one car. OverpopulationSince CO2 contributes to global warming, the increase in population makes the problem worse because we breathe out CO2. Also, the trees that convert our CO2 to oxygen are being demolished because we're using the land that we cut the trees down from as property for our homes and buildings. We are not replacing the trees (an important part of our eco system), so we are constantly taking advantage of our natural resources and giving nothing back in return.
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P - Productivity S - Speed R - Relevancy Price: $20.00 USD. Approx. 22,870 words. Language: English. Published on August 23, 2013. Category: Essay. How to Take Off Your ProfessionalCareer from an Average to Exceptional with the Hidden PSR in You. A Book By working CEO and Manager with Day to day and live Examples How to Fight with Global Recession. By Shekhar Gupta Surbhi MaheshwariPublished: Aug. 23, 2013 Words: 22,870 (approximate) Language: English ISBN: 9781301432448Be an Aviator Not a Pilot is a story of Pilots in Aviation who are unable to cope. This is not a book to teach you how to get into an Aviation School or even how to live like a Pilot. In fact, it describes how one can become a Successfull Aviator not just an Airplane Driver [ So called Pilot ] with very small changes in life. Also Why abroad trained Pilots are better Aviator and Why FAA, CASA, CAAP, CAA are better civil Aviation Authority then DGCA. by Shekhar Gupta Ankisha Awasthi
Be An Aviator not A Pilot Price: $1.99 USD. Approx. 4,750 words. Language: English. Published on July 24, 2013. Category: Fiction. As A Fact Out Of Every 1000 Pilots Only 1 Pilot Becomes AnAirline Pilot, The Book Is All About Those 999 Pilots Only.Pilot’s Career Guide Price: $20.00 USD. Approx. 25,040 words. Language: English. Published on July 13, 2013. Category: Nonfiction. International Airline Pilot’s Career Guide Learn Step By Step How to Become anInternational Airlines Pilot By Shekhar Gupta And Niriha KhajanchiCabin Crew Career Guide
Published: Aug. 26, 2013 Words: 2,160 (approximate) Language: English ISBN: 9781301001965
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