Chemistry-soaps And Detergents :: essays research papers

Cleaning with soap and soapless detergents. Detergent comes from the Latin word detergere meaning to clean, it is defined as a cleansing agent. Therefore, water itself is a detergent. This essay looks at soap and soapless (or synthetic) detergents. Both substances we use everyday and have a big market commercially, they effect everyone. Soaps are made from natural products and soapless detergents are produced chemically, each having advantages and disadvantages. Soap has a much longer history than it’s relatively new synthetic version. There is evidence of soap made in Mediterranean countries around 2500 years ago. The basic process has not changed much although now the chemistry is understood. Soap is made from the process called saponification, the alkaline hydrolysis of fats and oils. It is essentially the reverse of esterification. O O R-C-O-R’ + NaOH ---- R-C-O-Na+ + R’OH Ester(fat) + base(caustic soda) ---- salt of fatty acid(soap) + alcohol(glycerol). Caustic potash (potassium hydroxide) can be used instead of caustic soda (sodium hydroxide)but is more expensive. The base used to come from wood ash containing potassium carbonate which formed potash as this was not plentiful it made soap a luxury. The cheapest source of the ester is animal and vegetable fats and oils. H-H-H-H-H-H-H-H-H-H-H-H-H-H-H O H-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C H-H-H-H-H-H-H-H-H-H-H-H-H-H-H O-Na+ This is an example of a soap molecule. The hydrocarbon end is non polar and hydrophilic (water hating) and the carboxylate end is polar and hydrophilic (water loving). This the property which allows it to clean, it acts as an emulsifying agent. The soap disperses in water to form miscelles where a negatively charged surface is formed and hydrocarbon chains are in the centre. These miscelles surround droplets of dirt or grease suspending them in the water so they can be washed away. In soft neutral water soap works very well. However in hard water those containing ions (calcium and magnesium ions) the soap reacts with the ions forming insoluble salts, scum which settles on fabrics and around the bath. A scum is also the result when soap is used in acidic water. Soap is also affected by the nature of the dirt, for example perspiration breaks down the soap reducing the washing power. There are other disadvantages of soap, it deteriorates on storage lacks cleaning power and doesn’t rinse out completely. The production of synthetic detergents are an example of a standard chemical approach. If a useful substance has some undesirable properties an attempt is made to make a near copy synthetically which will perform better.

Before the Volcano Erupted: The Ancient Cerén Village in Central America

The archaeological site of Joya del Ceren, located in the broad Zapotitan Valley in the fertile region of western El Salvador, is a remarkable and important find that has been compared to the ancient ruined cities of Pompeii and Herculaneum in Italy. Like Pompeii, Joya del Ceren was preserved under layers of volcanic ash in the catastrophic Loma Caldera eruption from the nearby Ilopango volcano approximately 600 AD. This eruption forced the sudden abandonment of the site by its inhabitants who were forced to leave their possessions behind.Dr Payson Sheets of the University of Colorado-Boulder has been leading the excavations of the site, and as this ancient farming village of the Maya is now being revealed, many important insights into the household and community life of the ancient Maya, as well as their economic, social, and religious activities are becoming better understood. In Dr. Sheets’ book, Before the Volcano Erupted: The Ancient Ceren Village in Central America, an o verview of the knowledge gained by recent excavations is provided.The book opens with a discussion of volcanology, geophysics, and paleobotany. It is clear that the presence of the nearby volcanic hills around the site presented both benefits and hazards to the ancient inhabitants. The volcano provided a source of hard stones for making manos and metates, its ancient eruptions deposited a fertile bed of ash for fruitful agriculture, but it also proved the destruction of their village.What is so amazing is the fine state of preservation that the volcanic eruption gave to the material culture of the site. The buildings, complete with their thatched roofs (mice included) and painted walls, the beautifully painted gourds and pottery vessels, whole and filled with foodstuffs, liquid residues, utensils and other personal items, the craft tools, and the clear evidence of craft production are all on hand, looking untouched despite their fourteen centuries of age. Consider this remarkable st atement:â€Å"The numerous seasonally sensitive plants preserved at the site indicate the eruption probably occurred in August. Further, the positions and conditions of artifacts indicate the eruption probably occurred in the early evening, after dinner was served but before the dishes were washed, likely between 6:00 and 7:00 P. M. † (Sheets) For all the fury and destruction that volcanoes can cause, such an outcome is nevertheless a joy to historians and archaeologists, and should be to anyone curious about the lives of prehistoric peoples.The focus of the explorations at Joya del Ceren is centered on â€Å"Household Archaeology,† with the household being defined as â€Å"the domestic coresidential social and adaptive unit intermediate between the individual and the neighborhood. † (Sheets) Part II of the book describes the four households excavated prior to publication, with eleven building having been completely excavated, and seven others partially excavate d. Professor Sheets summarizes the work to date as follows:Four buildings of Household 1 have been excavated, including a domicile (for sleeping, eating, and various daytime activities), a storehouse, a kitchen, and a ramada-style building that occasionally was used for chipped stone tool maintenance, among other functions (Structures 1, 6, 11, and 5, respectively). Two buildings of Household 2 have been excavated, the domicile and the storehouse (Structures 2 and 7). The kitchen has yet to be excavated, and we do not know if Structure 18 is a part of this household.Only a part of the kitchen of Household 3 is known (Structure 16). The storehouse of Household 4 has been excavated, and it is a storehouse and much more (Structure 4). The maguey (Agave americana) garden south of the building produced fiber for about a dozen households; the leaves were depulped to liberate the fibers using Structure 4's northeast corner pole. † (Sheets) The results of these excavations revealed a good deal about household and village life of the people of the Maya frontier circa 600 AD.We have an expanded view of what they ate (maize, beans, chiles, squash, manioc, maguey, cacao and guayaba among others), the wealth they possessed (over 70 vessels in household 1 alone), and their source of livelihood (both subsistence farming and craft specialization). Indeed it is possible to speculate that each household produced a certain type of finished craft for export trade within or beyond the village.Sheets describes how â€Å"each household overproduced at least one craft or commodity and used that for exchange within the community and to obtain long-distance traded items that generally were produced by specialists, such as obsidian tools, hematite pigments, and jade axes. † (Sheets) It is shown how household 1 produced groundstone items such as manos and metates, and a tool called a donut stone. Household 2 likely served as a painted gourd factory, as evidenced by the prese nce of cinnabar paints and the use-wear on chipped stone tools found at the site.In addition to the household structures, some other community buildings have been identified. These include Structure 9, a large sweat bath that could accommodate a dozen people , structure 10, considered to be a religious festival building of some kind, as evidenced by the presence of some sacred artifacts, such as a deer skull headdress, and an obsidian blade with traces of human blood. There is also a large community center or civic complex, perhaps used for local government functions or religious purposes or both. The religious buildings were painted white and are the only white buildings found at the site.Some of the agricultural fields have been examined, and the results are very interesting. For example, the rows for maize were ridged, and some areas show where portions of the crop have already been harvested and the ground replanted with the second crop for the year. Many species of plants are i dentified by plaster casting, including â€Å"maize, beans, chiles, squash, manioc, maguey, various trees such as cacao and guayaba, and a number of palm and deciduous trees. † (Sheets) The manioc field is known as the first evidence of the cultivation of this crop in the Americas.In a recent CU-Boulder news release article, Sheets said â€Å"we have long wondered what else the prehistoric Mayan people were growing and eating besides corn and beans, so finding this field was a jackpot of sorts for us. Manioc's extraordinary productivity may help explain how the Classic Maya at huge sites like Tikal in Guatemala and Copan in Honduras supported such dense populations. † The work at Joya del Ceren is far from over. The book explains how the archaeologists are using ground penetrating radar equipment to locate numerous other buildings for future excavations.As time goes on, the riches of Joya del Ceren will continue to emerge from the ashes. Before the Volcano Erupted: The Ancient Ceren Village in Central America is a rather typical archaeological report, fairly dry for reading, but full of fascinating information if you take the time to pick through it. What is important is what the Archaeology of the site can teach us of the ancient people that lived there. The site must be an outstanding place to visit, for to see such well-preserved artifacts would surely spark the imagination.I would surely recommend the book to anyone interested in the Maya, in archaeology and history in general, or to anybody that is curious about the way that ordinary people from the past may have lived their lives. Works Cited Sheets, Payson. â€Å"CU-Boulder Archaeology Team Discovers First Ancient Manioc Fields In Americas. † CU-Boulder News. August 20, 2007. http://www. colorado. edu/news/releases/2007/305. html Sheets, Payson (ed. ) Before the Volcano Erupted: The Ancient Ceren Village in Central America. Boulder, Colorado. 2002

The Top 20 Figures of Speech

A figure of speech is a rhetorical device that achieves a special effect by using words in a distinctive way. Though there are hundreds of figures of speech,  here well focus on 20 top examples. Youll probably remember many of these terms from your English classes. Figurative language is often associated with literature and with poetry in particular. Whether were conscious of it or not, we use figures of speech every day in our own writing and conversations. For example, common expressions such as falling in love, racking our brains, and climbing the ladder of success are all metaphors—the most pervasive figure of all. Likewise, we rely on similes when making explicit comparisons (light as a feather) and hyperbole to emphasize a point (Im starving!). Did You Know? Figures of speech are  also known as  figures of rhetoric, figures of style, rhetorical figures,  figurative language,  and  schemes. 1:15 Watch Now: Common Figures of Speech Explained Top 20 Figures of Speech Using original figures of speech in our writing is a way to convey meanings in fresh, unexpected ways. They can help our readers understand and stay interested in what we have to say.   1.  Alliteration: The repetition of an initial consonant sound. Example: She sells seashells by the seashore. 2. Anaphora: The repetition of the same word or phrase at the beginning of successive clauses or verses. Example: Unfortunately, I was in the wrong place at the wrong time on the wrong day.   3. Antithesis: The juxtaposition of contrasting ideas in balanced phrases. Example: As Abraham Lincoln said, Folks who have no vices have very few virtues. 4.  Apostrophe: Directly addressing a nonexistent person or an inanimate object as though it were a living being. Example: Oh, you stupid car, you never work when I need you to, Bert sighed. 5. Assonance: Identity or similarity in sound between internal vowels in neighboring words. Example: How now, brown cow? 6. Chiasmus: A verbal pattern in which the second half of an expression is balanced against the first but with the parts reversed. Example: The famous chef said people should live to eat, not eat to live. 7. Euphemism: The substitution of an inoffensive term for one considered offensively explicit.  Example: Were teaching our toddler how to go potty, Bob said. 8.  Hyperbole: An extravagant statement; the use of exaggerated terms for the purpose of emphasis or heightened effect. Example: I have a ton of things to do when I get home. 9.  Irony: The use of words to convey the opposite of their literal meaning. Also, a  statement or situation where the meaning is contradicted by the appearance or presentation of the idea. Example: Oh, I love spending big bucks, said my dad, a notorious penny pincher. 10.  Litotes: A figure of speech consisting of an understatement in which an affirmative is expressed by negating its opposite. Example: A million dollars is no small chunk of change. 11.  Metaphor: An implied comparison between two dissimilar things that have something in common. Example: All the worlds a stage. 12.  Metonymy: A figure of speech in which a word or phrase is substituted for another with which it is closely associated; also, the rhetorical strategy of describing something indirectly by referring to things around it. Example: That stuffed suit with the briefcase is a poor excuse for a salesman, the manager said angrily. 13.  Onomatopoeia: The use of words that imitate the sounds associated with the objects or actions they refer to. Example: The clap of thunder went bang and scared my poor dog. 14.  Oxymoron: A figure of speech in which incongruous or contradictory terms appear side by side. Example:  He popped the jumbo shrimp in his mouth. 15.  Paradox: A statement that appears to contradict itself. Example: This is the beginning of the end, said Eeyore, always the pessimist. 16. Personification: A figure of speech in which an inanimate object or abstraction is endowed with human qualities or abilities. Example: That kitchen knife will take a bite out of your hand if you dont handle it safely. 17.  Pun: ​A play on words, sometimes on different senses of the same word and sometimes on the similar sense or sound of different words. Example: Jessie looked up from her breakfast and said, A boiled egg every morning is hard to beat. 18.  Simile: A stated comparison (usually formed with like or as) between two fundamentally dissimilar things that have certain qualities in common. Example: Roberto was white as a sheet after he walked out of the horror movie. 19.  Synecdoche: A figure of speech in which a part is used to represent the whole. Example: Tina is learning her ABCs in preschool. 20. Understatement: A figure of speech in which a writer or speaker deliberately makes a situation seem less important or serious than it is. Example: You could say Babe Ruth was a decent ballplayer, the reporter said with a wink.