Chem Notes Igcse Essay Example for Free

Chem Notes Igcse Essay Giant Covalent Structures There are 2 examples of Giant covalent structures: Diamond Graphite They are both  allotropes  of carbon, meaning they are  both different  types of the physical  form of Carbon. Diamond Structure: Giant covalent  lattice  of carbon atoms. Each Carbon atom is bonded to 4 others which tetrahedrally surround the atom. They have a  high melting point  as a large amount of heat energy is needed to break their bonds. They are  unable  to conduct electricity as they have no free mobile  electrons to carry the current. Diamond is very  hard  as there are many bonds within the substance. It is the hardest natural substance and is often used in drilling. Graphite Structure: Arranged in  layers  of atoms. Each carbon atom is joined to 3 others, leaving one outer shell electron on each carbon is free to move and able to cary the current. Therefore, they are able to conduct electricity. Graphite also has a high melting point for the same reasons as diamond. However, it is not hard like diamond but in fact very soft. There are weak forces between  the  layers of atoms. They  are able to slide over each other and therefore able to act as a lubricant. Covalent Bonding Definition:  When an atom shares one or more pairs of electrons between atoms to obtain the electronic configuration of a noble gas. Covalent bonds appear in  non-metals  and create  molecules. They can even appear in atoms of the same element,  H2. Molecule:  Two or more atoms  chemically  bonded together. The covalently bonded atoms are held together by  strong attraction  between the  bonding pair of electrons  and the  nuclei  of the atoms. Covalent bonds can be classified into  two  groups:  simple molecular  structures   giant covalent  structures Simple molecular Structures: They have low melting/boiling points due  to the fact that  there  are  weak  intermolecular forces of attraction. Although, they do have strong covalent bonds. Therefore, they need less heat energy to overcome and break the weak bonds. Some substances  sumblime  under heating. i. e. They turn directly into a gas from a solid. Giant molecular Structures:  See post on giant Molecular structures , Ionic Bonding Definition:  The transfer of one or more electrons between 1 atom to another Why? To obtain the electronic configuration of a noble gas. This  is because noble gases are inert/very unreactive. If an atom  loses  an electron then the atom will form a  positive  ion. This is because there are now more protons than electrons in the atom. If an atom  gains  an electron, the atom forms a  negative  ion as there are now more electrons than protons in the atom. The  charge  of an ion is related to where the element’s position is in the periodic table.

The Social Media In Our Life Media Essay

The Social Media In Our Life Media Essay Many people have used social media at least once in their lives. According to Peggy Orenstein, most people agree that social-networking sites have allowed users to connect with people in ways they never could before (p. 40). Thanks to social networking sites, we can share anything with many contacts in just a matter of seconds. We can do this whenever we want to and from anywhere we are (technology permitting). Sites like Facebook and Twitter have become more and more a part of our life, both directly and indirectly. They are used by various people for myriad reasons and in different ways. Some of this reasons and ways have generated much criticism. But they keep being used more and more. Social networking sites are not perfect; however, they have shown their strength and their ability to withstand time. Many writers look at social networking sites with a critical eye. In her essay, Faceless on Facebook, Kate Beals says: The personal area on Facebook is less about the real you and more about what you want people to think about you (p. 49). She points out how social networking users might be constructing their online image, by critically assessing every information or post they put online, instead of sincerely showing themselves and not worrying about the image it would give of them. Beals herself epitomizes this, for she is constantly worried about how people would look at her, through her personal page. Another critique is that social media encourage users to keep posting every thought or acts online. This encourages quantity over quality as Christine Rosen says in her essay, Virtual Friendship and the New Narcissism (p. 59). And I also agree with her thought: True friendship can only flourish within the boundaries of privacy because it depends on mutual revelations that are conceal ed from the rest of the world therefore the idea of public friendship is an oxymoron (p. 56). Social networking sites can help by creating a virtual contact between people, but we need much more than that if we want to create a true friendship. Even though both of these writers have a point, they are missing the true strength of social networking sites like Facebook and Twitter. Practicality is the most appealing positive aspect of social media. Not so many years ago, if we wanted to share the adventure we had during a wonderful trip to Europe, we would have needed to meet a friend in person, catch them up on the phone or send them an e-mail and wait for an eventual response. If we wanted to show a specific picture of the Coliseum, we would have first needed to print it, put it into a photo album and wait for them to visit us. Today, we would post every picture right after we take it with our phone. We would share our adventures right after we experience them. This way all our friends or followers (as they are called on Twitter) would be able to enjoy our antics instantly. But is practicality the only strength of social media? Facebooks website says there were 955 million monthly active users at the end of June 2012 (facebook.com). That number equals a seventh of the worlds population. There has to be more to social networking sites than simple practicality. In his essay, You Gotta Have (150) Friends, Robin Dunbar says: Emotional closeness declines by around 15 percent a year in the absence of face-to-face contact (p. 46). Whether or not accurate, this statement has been true for me. When I moved from Albania to Italy, I had to say goodbye to many good friends. This happened in 2001, and back then, the only way of communicating for us was phone calls. Since those calls were not so cheap, my friends and I rarely made them. By the end of the year we were feeling both, physical and emotional distance. Lately, I had another life-changing moment. Just a month ago I said goodbye to Italy (and all my friends there) and came to the United States. After this se paration, I had much more reliable and costless ways to communicate with my friends. This way we can keep our emotional bond alive no matter how far we are from each other. I am confident that we will not end up like my Albanian friends and me. This is, by a fair amount, because of social media. In the same way social networking sites are used to keep up with friends, they can also be used to keep up with the world. Many communication media use websites such as Facebook to keep people informed on virtually everything. Many celebrities, journalists and even political figures have a public page on Facebook, or they tweet regularly. President Obama, trying to attract younger voters, used social networking websites extensively during his 2008 presidential campaign. One of the defining moments for social networking sites, especially Twitter, was their usage during the revolutionary uprisings in different Arab countries in late 2010, also known as Arab Spring. During that period, I noticed the amount of input that news media took from social networking sites. I do not know if social media were a catalyst for the uprisings or simply tools used during these events, but they undeniably played a role. Besides sharing information about ourselves and the world around us, social networking sites can be a powerful marketing tool. A positive post on a certain product, made by a close friend, is much more powerful than a commercial. When I need to decide on what to buy, or I need to know how good specific restaurants are, I always rely on what my friends think about it. A perfect example for this is Foursquare. Foursquare is an application for mobile phones. It gives you the opportunity to check in into specific places, and leave comments about your experience while visiting those places. All these check-ins and comments are shared instantly with your friends. The better the rating a particular place has, the higher the possibility I will go there. No matter how we look at them, social networking sites have built a strong position in our society during these last years. They have given us some powerful communication tools. Whether or not we choose to be a part of social media, there will always be somebody that will use them according to their needs.

The Importance of Weather in Kate Chopins The Storm :: Chopin Storm Essays

The Importance of Weather in The Storm      The Storm, by Kate Chapin, is a short story about two people that have and affair during a storm.   Basically, it’s like this.   The story involves two families, that of Bobinot, Calixta, and Bibi, and Alcee, Clarisse, and their babies.   Calixta is at her house separated from her family due to the storm.   Alcee is separated from his family because they are visiting another town.   The storm brings Calixta and Alcee together and they have an affair.   It s set in a small town in the late 1800s.   A storm can mean many things, both good and bad, and it is important to the story both symbolically and directly.      Ã‚  Ã‚   The storm acts as a catalyst in the story as it causes the events to unfold as they do.   The first real direct effect the storm has in the story is that it is what causes Bobinot and Bibi to stay at the local store to take shelter.   This of course leaves Calixta home alone.   Alcee, we are lead to believe, was out riding his horse somewhere near Calixta s house when the storm started.   This causes him to take shelter there.      Ã‚  Ã‚   Before Calixta got married five years earlier, the two had romantic feelings toward each other.   They rarely saw each other after that, and this what the first time since then that they had been alone together.   Because of the awkward feelings he had, Alcee   expressed an intention to remain outside (666).   This is where the storm, because it is a rather big storm, forces him to go inside.   Once inside it seems harmless conversation would be all that took place.   But alas, the storm once again comes into play.   While Calixta, worried about her family, it looking out the window the storm sends down a huge lightning bolt into a tree nearby.   This causes her to jump and for Alcee to instinctively grab her in his arms.   The storm now comes into play one last time.   As Calixta is nervously pacing around the house (because of the storm), Alcee grabs her shoulders in an attempt to calm her down.   At this point their old feelings become too overwh elming resulting in an affair.   When the storm ends, it symbolizes the end of the affair.   We are never told what Chapin meant by the title   The Storm.

René Magritte Essay -- Arts Paintings Art History

Renà © Magritte Belgian Surrealist artist Renà © Magritte was a master not only of the obvious, but of the obscure as well. In his artwork, Magritte toyed with everyday objects, human habits and emotions, placing them in foreign contexts and questioning their familiar meanings. He suggested new interpretations of old things in his deceivingly simple paintings, making the commonplace profound and the rational irrational. He painted his canvasses in the same manner as he lived his life -- in strange modesty and under constant analysis. Magritte was born in 1898 in the small town of Lessines, a cosmopolitan area of Belgium that was greatly influenced by the French. Twelve years later, Magritte, along with his parents and two younger brothers, moved to Chà ¢telet, where the future artist studied sketching. On vacations with his grandmother and Aunt Flora during the summer months, Magritte frequented an old cemetery at Soignies. In this cemetery, Magritte often played with a little girl, opening trap doors and descending into underground vaults. This experience would prove a great influence upon his later artwork, as wooden caskets and granite tombstones recur in many of his paintings. Magritte also developed a fascination with religion around this time, often dressing up as a priest and holding mock mass services in complete seriousness. In 1912, Rà ©gina Bertinchamp, Magritte's mother, committed suicide by drowning herself in the Sambre River. The night of her suicide, the Magrittes followed Bertinchamp's footprints to the river, where they found her dead with her nightgown wrapped around her face. Magritte was 14 at the time. He would claim years later that his only recollection of his mother's death was his pride at being the center of attention and his subsequent identity formation as the "son of a dead woman." Some critics point out that several of the subjects in Magritte's paintings are veiled in white sheets as a reference to his mother's suicide. A year later, Magritte's father moved the family to Charleroi. It was in Charleroi that Magritte would meet his future wife Georgette Berger on a carousel at the town fair. However, the two would not see one another again until a chance meeting in Brussels years later. In Charleroi, Magritte quickly lost interest in his studies and asked his father for permission to study at the Acadà ©mie des Beaux-Arts in Brussels. ... ... Faubourg in Paris. The exhibition caused much scandal, but won few admirers. Soon after, Magritte resigned to his original style, though he bitterly attributed this retroaction to his desire to please Georgette, who preferred his earlier paintings. He continued to acquire much success all over the world with paintings such as L'Empire des Lumià ¨res (The Empire of Lights, 1954), which employed standard Surrealist techniques and precise Magritte lines. On August 15, 1967, Magritte died in Brussels. Unlike many of his Surrealist counterparts, Magritte lived quite humbly and incon uously. He did not draw much attention to himself, and he lived life relatively uneventfully. Despite his unassuming lifestyle, though, Magritte managed to leave an artistic legacy of transforming the ordinary into the fantastic. While some art historians attribute Magritte's art to his desire to oppose and combat the triviality of everyday life, others suggest that his work goes beyond escapism and serves to reveal some of the murkier and complex aspects of the human condition. Whatever the impetus was for his art, it is certain that Magritte's works are at once hauntingly beautiful and deeply provocative.

Cathy Ames as the Devil in John Steinbecks East of Eden Essay

Cathy Ames as the Devil  in East of Eden    East of Eden was a novel that explored the roots of evil in its most primal form. Through intricate plot lines and complex characters, John Steinbeck weaved a tale of brutality, cruelty, and isolation. One important character that helped to illustrate the presence of evil throughout the book was Cathy Ames, an intelligent woman who ruthlessly used other people to serve her own needs. When reflecting upon East of Eden, a debate that often surfaces is whether Cathy's evil was a result of nature or nurture. Arguments for and against both sides are in the book. At some times, Cathy is portrayed as a wicked fiend who's aggression stems from nowhere but her own empty heart. Other times, Cathy appears weak and afraid of people who aren't the least bit intimidating. Those are the moments in the book where one must question whether Cathy is truly evil, or just an impatient and self-centered individual.    Cathy's upbringing did not seem to be a likely place to foster dissent and animosity in the young girl. Her pa...

Martin Luther King, Jr.’s Fight for Integration

Martin Luther King Jr. once said, â€Å"I have a dream that one day little black boys and girls will be holding hands with little white boys and girls,† (â€Å"goodreads†). His â€Å"I Have a Dream† speech took place in 1963 during the March on Washington. It was there that he established his reputation as one of the greatest orators in American history. Martin Luther King Jr. ’s American dream was that all men should have god-given rights and have equality. To achieve this American dream, Martin Luther King Jr. faced many obstacles to overcome discrimination. Before Martin Luther King Jr. chieved his American dream, there were many obstacles in the way; it was not all fun and games. The first one was the difficulty to convince African Americans because they believed that they should fight back against discrimination. The police were also another obstacle Martin had to face. During the civil rights movement, the police would use dogs and fire hoses towards the blacks to settle boycotts that were conducted. However, Martin would never use violence back. Another problem that he faced was prejudice ideas. Many whites had opinions about African Americans that kept opportunities for them very limited.Martin never let any of these obstacles stop him from achieving his dreams of equality. Through all the difficulties Martin Luther King Jr. had to face, his American dream never changed. Martin wanted all men to have god-given rights and equality. He had to prove to his own people, the police, and the rest of America that it was possible to stand up for themselves without being violent. With this belief, Americans realized that the white society was in the wrong when it came to discrimination and violence because African Americans were not harming anybody. This helped Martin’s dream become a reality.Work cited: Quote by Martin Luther King Jr. † goodreads. Otis Chandler. 28 Aug. 1963. Thur. 8 Nov. 2012. Haberman, Frederick.  "Martin Luther King-Biography. † Nobleprize. org. Les Prix Nobel. N. d. Web. 6 Nov. 2012. Roland, Allen. â€Å"Martin Luther King/ The Voice That Can’t Be Silenced. † Thepeoplesvoice. ord. n. d. 17 Jan. 2011. Web. 6 Nov. 2012. â€Å"Quote by Martin Luther King Jr. † goodreads. Otis Chandler. 28 Aug. 1963. Thur. 8 Nov. 2012. Carson, Clayborne. â€Å"Life. † Encyclopedia of African-American Culture and History. Ed. Colin A. Palmer. 2nd. Ed. Vol. 3. Detroit: Macmillan Reference USA, 2006. 1239-1243. Gale U. S. History In Context. Web. 7 Nov. 2012.

A Fast Way to a Fast Food Essay

According to a recent survey, the UK is particularly fond of fast food. Many people turn to fast food as it is quick, convenient, and relatively cheap even though there are many concerns over public health and obesity. With a large number of fast food chains available, how do likes of McDonald’s, Subway, and Pret. A merger maintain their market share at a time when people are cutting back on their spending? In the 10 largest UK cities, the number of fast-food outlets increased by 8,2 percent, to 1.456 in 2009 (the highest growth occurred in London, Edinburgh, and Glasgow). Among the UK’s biggest chains, Subway grew faster than others. The number of Subway restaurants increased by 25,9 percent to 734 in 2009. In the same year, Domino’s pizza (DPZ) increased its outlets by 19,8 percent to 260 and E A T increased its outlets by 17,8 percent to 86. The growth of these chains is considered as a success particularly when competing against other giant chains such as McDonald’s, Burger King, KFC, and Wimpy’s. Although fast food chains provide quick and efficient service, their operation models are different. In the traditional model, like Mc Donald’s, customers enter the restaurant, study the menu panels for a short period, and stand in the shortest line (behind the many counters). When the customer reaches the front of the line, he or she places an order, pays at the register, and collects the food within few minutes. When, a customer requests a nonstandard item, for example a burger with no tomatoes or extra bacon and cheese, the order is not available in the prestocked food area. The counterperson calls the order in to the production area. The item is then prepared to order as a priority. The waiting time is a bit longer in this case. Not all fast food chains in the UK follow the same customer service operational model. They have tried some innovative ideas to serve customers quicker and have more options and flexibility. In Subway, sandwich is prepared right in front of the customer, where the customer can select what type of bread, size, and sandwich fillings. The sandwich is normally ready in a couple of minutes and passed to the customer as soon as the customer pays for the food. Domino’z Pizza offers home delivery for a wide range of its pizzas, which can be personalized as well, in less than 20 minutes, while it does not charge for the delivery. Pizza Hut offers an open buffet as part of its service, to reduce the workload on its staff and give its customers more options with less price. In Pret A Manger and EAT, a set of sandwiches, salads, and desserts are assembled each day and stocked in the front of the shop where the customers select and pay for their meals. The stock level is then replenished during the day in line with demand. The aim is to continually meet the high quality and freshness standards. If any of the product assembled that day have not sold by the time the store closes, they are given to local charities rather than being stored and sold the following day.