Endergonic vs Exergonic Reactions and Processes

Endergonic vs Exergonic Reactions and Processes Endergonic and exergonic are two types of chemical reactions, or processes, in thermochemistry or physical chemistry. The names describe what happens to energy during the reaction. The classifications are related to endothermic and exothermic reactions, except endergonic and exergonic describe what happens with any form of energy, while endothermic and exothermic relate only to heat or thermal energy. Endergonic Reactions Endergonic reactions may also be called an unfavorable reaction or nonspontaneous reaction. The reaction requires more energy than you get from it.Endergonic reactions absorb energy from their surroundings.The chemical bonds that are formed from the reaction are weaker than the chemical bonds that were broken.The free energy of the system increases.  The change in the standard Gibbs Free Energy (G) of an endergonic reaction is positive (greater than 0).The change in entropy (S) decreases.Endergonic reactions are not spontaneous.Examples of endergonic reactions include endothermic reactions, such as photosynthesis and the melting of ice into liquid water.If the temperature of the surroundings decreases, the reaction is endothermic. Exergonic Reactions An exergonic reaction may be called a spontaneous reaction or a favorable reaction.Exergonic reactions release energy to the surroundings.The chemical bonds formed from the reaction are stronger than those that were broken in the reactants.The free energy of the system decreases.  The change in the standard Gibbs Free Energy (G) of an exergonic reaction is negative (less than 0).The change in entropy (S) increases. Another way to look at it is that the disorder or randomness of the system increases.Exergonic reactions occur spontaneously (no outside energy is required to start them).Examples of exergonic reactions include exothermic reactions, such as mixing sodium and chlorine to make table salt, combustion, and chemiluminescence (light is the energy that is released).If the temperature of the surroundings increases, the reaction is exothermic. Notes About the Reactions You cannot tell how quickly a reaction will occur based on whether it is endergonic or exergonic. Catalysts may be needed to cause the reaction to proceed at an observable rate. For example, rust formation (oxidation of iron) is an exergonic and exothermic reaction, yet it proceeds so slowly its difficult to notice the release of heat to the environment.In biochemical systems, endergonic and exergonic reactions often are coupled, so the energy from one reaction can power another reaction.Endergonic reactions always require energy to start. Some exergonic reactions also have activation energy, but more energy is released by the reaction than what is required to initiate it. For example, it takes energy to start a fire, but once combustion starts, the reaction releases more light and heat than it took to get it started.Endergonic reactions and exergonic reactions are sometimes called reversible reactions. The quantity of the energy change is the same for both reactions, although the en ergy is absorbed by the endergonic reaction and released by the exergonic reaction. Whether the reverse reaction actually can occur is not a consideration when defining reversibility. For example, while burning wood is a reversible reaction theoretically, it doesnt actually occur in real life. Perform Simple Endergonic and Exergonic Reactions In an endergonic reaction, energy is absorbed from the surroundings. Endothermic reactions offer good examples, as they absorb heat. Mix together baking soda (sodium carbonate) and citric acid in water. The liquid will get cold, but not cold enough to cause frostbite. An exergonic reaction releases energy to the surroundings. Exothermic reactions are good examples of this type of reaction because they release heat. The next time you do laundry, put some laundry detergent in your hand and add a small amount of water. Do you feel the heat? This is a safe and simple example of an exothermic and thus exergonic reaction. A more spectacular exergonic reaction is produced by dropping a small piece of an alkali metal in water. For example, lithium metal in water burns and produces a pink flame. A glow stick is an excellent example of a reaction that is exergonic, yet not exothermic. The chemical reaction releases energy in the form of light, yet it doesnt produce heat.

Characteristics of Ancient Monumental Architecture

Characteristics of Ancient Monumental Architecture The term monumental architecture refers to large humans include pyramids, large tombs, and burial mounds, plazas, platform mounds, temples and churches, palaces and elite residences, astronomical observatories, and erected groups of standing stones. The defining characteristics of monumental architecture are their relatively large size and their public nature- the fact that the structure or space was built by lots of people for lots of people to look at or share in the use of, whether the labor was coerced or consensual, and whether the interiors of the structures were open to the public or reserved for an elite few.   Who Built the First Monuments? Until the late 20th century, scholars believed that monumental architecture could only be constructed by complex societies with rulers who could conscript or otherwise convince the residents into working on large, non-functional structures. However, modern archaeological technology has given us access to the earliest levels of some of the most ancient tells in northern Mesopotamia and Anatolia, and there, scholars discovered something amazing: monumentally-sized cult buildings were constructed at least 12,000 years ago, by what started out as egalitarian hunters and gatherers. Before the discoveries in the northern Fertile Crescent, monumentality was considered costly signaling, a term that means something like elites using conspicuous consumption to demonstrate their power. Political or religious leaders had public buildings built to indicate that they had the power to do so: they certainly did that. But if hunter-gatherers, who ostensibly didnt have full-time leaders, built monumental structures, why did they that do that? Why Did They Do That? One possible driver for why people first started building special structures is climate change. Early Holocene hunter-gatherers living during the cool, arid period known as the Younger Dryas were susceptible to resource fluctuations. People rely on cooperative networks to get them through times of social or environmental stress. The most basic of these cooperative networks is food sharing. Early evidence for feasting- ritual food sharing- is at Hilazon Tachtit, about 12,000 years ago. As part of a highly organized food-sharing project, a large-scale feast can be a competitive event to advertise community power and prestige. That may have led to the construction of larger structures to accommodate larger numbers of people, and so forth. It is possible that the sharing simply stepped up when the climate deteriorated. Evidence for the use of monumental architecture as evidence for religion usually involves the presence of sacred objects or images on the wall. However, a  recent study by behavioral psychologistsYannick Joye and Siegfried Dewitte (listed in the sources below) has found that tall, large-scale buildings produce measurable feelings of awe in their viewers. When awe-struck, viewers typically experience momentary freezing or stillness. Freezing is one of the main stages of the defense cascade in humans and other animals, giving the awe-struck person a moment of hyper-vigilance toward the perceived threat. The Earliest Monumental Architecture The earliest known monumental architecture is dated to the periods in western Asia known as pre-pottery Neolithic A (abbreviated PPNA, dated between 10,000–8,500 calendar years BCE [cal BCE]) and PPNB ( 8,500–7,000 cal BCE). Hunter-gatherers living in communities such as Nevali Çori, Hallan Çemi, Jerf el-Ahmar, D’jade el-Mughara, Çayà ¶nà ¼ Tepesi, and Tel Abr all built communal structures (or public cult buildings) within their settlements. At Gà ¶bekli Tepe, in contrast, is the earliest monumental architecture located outside of a settlement- where it is hypothesized that several hunter-gatherer communities gathered regularly. Because of the pronounced ritual / symbolic elements at Gà ¶bekli Tepe, scholars such as Brian Hayden have suggested that the site contains evidence of emergent religious leadership. Tracing the Development of Monumental Architecture How cult structures might have evolved into monumental architecture has been documented at Hallan Çemi. Located in southeastern Turkey, Hallan Cemi is one of the oldest settlements in northern Mesopotamia. Cult structures significantly different from regular houses were constructed at Hallan Cemi about 12,000 years ago, and over time became larger and more elaborate in decoration and furniture. All of the cult buildings described below were located at the center of the settlement and arranged around a central open area about 15 m (50 ft) in diameter. That area contained dense animal bone and fire-cracked rock from hearths, plaster features (probably storage silos), and stone bowls and pestles. A row of three horned sheep skulls was also found, and this evidence together, say the excavators, indicates that the plaza itself was used for feasts, and perhaps rituals associated with them. Building Level 3 (the oldest): three C-shaped buildings made of river pebbles about 2 m (6.5 ft) in diameter and mortared with white plasterBuilding Level 2: three circular river-pebble buildings with paved floors, two 2 m in diameter and one 4 m (13 ft). The largest had a small plastered basin in the center.Building Level 1: four structures, all constructed of sandstone slabs rather than river pebbles. Two are relatively small (2.5 m, 8 ft in diameter), the other two are between 5-6 m (16-20 ft). Both of the larger structures are fully circular and semi-subterranean (excavated partly into the ground), each with a distinctive semicircular stone bench set against the wall. One had a complete auroch skull which apparently hung on the north wall facing the entrance. The floors had been resurfaced multiple times with a distinctive thin yellow sand and plaster mixture over a relatively sterile fine dirt fill. Few domestic materials were found inside the structures, but there were exotics, including copper ore and obsidian. Examples Not all monumental architecture was (or is for that matter) built for religious purposes. Some are gathering places: archaeologists consider plazas a form of monumental architecture since they are large open spaces built in the middle of town to be used by everyone. Some are purposeful- water control structures like dams, reservoirs, canal systems, and aqueducts. Sports arenas, government buildings, palaces, and churches: of course, many different large communal projects still exist in modern society, sometimes paid for by taxes. Some examples from across time and space include Stonehenge in the UK, the Egyptian Giza Pyramids, the Byzantine Hagia Sophia, the Qin Emperors Tomb, the American Archaic Poverty Point earthworks, Indias Taj Mahal, Maya water control systems, and the Chavin culture Chankillo observatory. Sources Atakuman, Çigdem. Architectural Discourse and Social Transformation During the Early Neolithic of Southeast Anatolia. Journal of World Prehistory 27.1 (2014): 1-42. Print. Bradley, Richard. Houses of Commons, Houses of Lords: Domestic Dwellings and Monumental Architecture in Prehistoric Europe. Proceedings of the Prehistoric Society 79 (2013): 1-17. Print. Finn, Jennifer. Gods, Kings, Men: Trilingual Inscriptions and Symbolic Visualizations in the Achaemenid Empire. Ars Orientalis 41 (2011): 219-75. Print. Freeland, Travis, et al. Automated Feature Extraction for Prospection and Analysis of Monumental Earthworks from Aerial Lidar in the Kingdom of Tonga. Journal of Archaeological Science 69 (2016): 64-74. Print. Joye, Yannick, and Siegfried Dewitte. Up Speeds You Down. Awe-Evoking Monumental Buildings Trigger Behavioral and Perceived Freezing. Journal of Environmental Psychology 47.Supplement C (2016): 112-25. Print. Joye, Yannick, and Jan Verpooten. An Exploration of the Functions of Religious Monumental Architecture from a Darwinian Perspective. Review of General Psychology 17.1 (2013): 53-68. Print. McMahon, Augusta. Space, Sound, and Light: Toward a Sensory Experience of Ancient Monumental Architecture. American Journal of Archaeology 117.2 (2013): 163-79. Print. Stek, Tesse D. Monumental Architecture of Non-Urban Cult Places in Roman Italy. A Companion to Roman Architecture. Eds. Ulrich, Roger B. and Caroline K. Quenemoen. Hoboken, New Jersey: Wiley, 2014. 228-47. Print. Swenson, Edward. Moche Ceremonial Architecture as Thirdspace: The Politics of Place-Making in the Ancient Andes. Journal of Social Archaeology 12.1 (2012): 3-28. Print. Watkins, Trevor. New Light on Neolithic Revolution in South-West Asia. Antiquity 84.325 (2010): 621–34. Print.

Accounting for non-profit company Essay Example | Topics and Well Written Essays - 2000 words

Accounting for non-profit company - Essay Example Rotary International is a not-for-profit organization that was founded on February 23, 1905 by the Chicago attorney, Paul P. Harris. The Rotary Club of Chicago provided a platform where diverse professionals would exchange ideas, forming meaningful and lifelong relationships. The name, â€Å"Rotary† came from the fact that earlier members used to rotate in each others’ offices for meetings. With its growth, Rotary International aimed at bringing together professional and business leaders so as to render humanitarian services, promote utmost ethical standards in various vocations and foster global goodwill and peace, this being in line with its motto of â€Å"Service above self.† In its structure are Rotary clubs, Rotary International and Rotary Foundation. This paper focuses on the Rotary International, RI which is the umbrella body supporting Rotary clubs across the globe and coordinates global campaigns, programs and initiatives. The mission of RI is to â€Å" provide service to others, promote integrity, and advance world understanding, goodwill, and peace through its fellowship of business, professional, and community leaders† (Rotary International, 2014). It is therefore a model of a charitable organization seeking to promote social interests in various communities around the world. RI has its world headquarters based in Evanston, IL in the US. It has international offices in Zurich, New Delhi, Tokyo, Yongdungpo-gu, Parramatta, Sà £o Paulo and Buenos Aires serving Europe/Africa, South Asia, Japan, Korea, South Pacific and Philippines, Brazil and Southern South America regions respectively. They also have offices in Great Britain and Ireland. Through this network, Rotary International, RI (2014) documents a current membership of 1.2 million people. These regions contribute towards the total donation income of RI. The presidency is the topmost position in RI. According to RI (2014), the president leads and motivates the members, ensuring they feel