Chemistry Lab Essay Example

Chemistry Lab Essay Example Chemistry Lab Essay Chemistry Lab Essay Physical and Chemical Change Objective: Recognize and distinguish between chemical and physical changes. Materials: lab balance lab burner 5 test tubes test tube rack test tube holder watch glass glass square microspatula dropper pipet mortar and pestle magnet insulating pad safety goggles lab apron or coat copper sulfate pentahydrate iron fillings sodium chloride hydrochloric acid silver nitarate sulfur Procedure: magnesium ribbon paper (5 cm x 10 cm) birthday candle matches 1. Place a small amount of wax from a birthday candle into a test tube. Heat gently ver a burner flame until the wax melts completely; then allow the sample to cool. Next, light the candle, secure it to a glass square, and allow it to burn until it extinguishes itself. Proceed with rest of the experiment while the candle burns. 2. Tear a piece of paper (about 5 cm x 10 cm) into small pieces. Set a watch glass on an insulating square and place the pieces of paper on the glass. Ignite the paper with a match and allow to burn. . Add a microspatula of NaCl (sodium chloride) to a small quantity of water (about 5mL) in a test tube. Shake the contents of the tube. Next, use a dropper to add 10 drops of 0. silver nitrate to the NaCl-water mixture. 4. Obtain a piece of magnesium ribbon about 5 cm long. Tear the ribbon into I-cm pieces. Place two of the pieces into a test tube and a few drops of 6 M HCI (hydrochloric acid). Caution: Use extreme care in handling this acid. It will cause severe bur ns if allowed to come in contact with the skin. Touch the bottom of the test tube with your fingertip. 5. Use a mortar and pestle to grind several crystals of CuS04 5H20 into a uniform powder. Place one microspatula of the powder into a test tube. Heat gently over a burner flame for 5 minutes. Allow the sample to cool and then add a few drops of ater. 6. Using a lab balance, measure out the following samples: ). 50 g of iron fillings and 0. 50 g of powdered sulfur. Test each sample with a magnet. Mix the two samples thoroughly in a test tube. Run the magnet along the bottom and sides of the test tube. Observations and Data: Procedures Description of what Happened Type of change Melting a wax test tube Wax turned to liquid Physical change (melting is a phase change) Melting a candle Melted down to nothing Chemical change (carbon dioxide was produced since candle was burned) Burning paper Turned to ashes Chemical change (carbon dioxide is produced) Mixed NaCl water. NaCl dissolved in water Physical change (homogenous mixture) AgN03 added to salt water mixture Mixture turned white Physical change (change in color) Water was added to test tube containing HCI Bubbling occurred and test tube heated up. Chemical; the bubbling meant that there was a production of a new substance which was hydrogen gas) Copper sulfate was heated Turned white Water was added to copper sulfate after it was heated Turned back to blue Physical change (color change) Iron fillings were mixed with sulfur Magnet was used to separate the iron fillings Physical change (mixtures can be separated physically) Iron and sulfur were heated Iron lost its conductivity. Physical change (conductivity is a physical property) When elements combine and form a compound they have different properties then when they exist in their elemental form. Conclusions and Questions 1. . Melting candle wax physical g. tearing Mg ribbon physical b. burning a candle chemical h. adding HCI to Mg c. tearing a paper physical i. grinding CuS04 5H20 physical d. burning paper chemical J. heating CuS04 5H20 chemical e. dissolving NaCl physical mixing Fe and S physical f. mixing NaCl and AgN03- l. heating a mixture of Fe and S chemical 2. Two possible indications that a chemical change has taken place are bubbling of a substance and burning of paper. For example, in the experiment when I poured Hydrochloric acid in a test tube and then one magnesium ribbon, the substances started to bubble. Other than that, when I took the wooden split and lit it, I burned the green paper and it changed brown around the edges of the paper. 3. The new substances that were formed as a result of chemical change were many. When I took the candle and lit it, it burnt and formed smoke. When I took the wooden split and lit the paper on fire, the color around the green paper changed to be brown, urnt and changed into ashes. Also, I poured Hydrochloric acid and magnesium ribbon in a test tube and it started bubbling and it heated up in the bottom. 4. The following examples do not always indicate chemical change. For example, change in color will always indicate chemical change because the color changes but it does not change the substances physical properties. The apparent loss in mass is a phase change; therefore the entire substance goes through a physical change. The apparent disappearance of a substance is a chemical change and will always be a hemical change because it might result of a soluble substance dissolving in a liquid and changes the entire substance in a chemical phase. . Substances in a mixture can be separated depending on the substances involved. You can use a magnet to separate a magnetic substance form a non-magnetic one, filtering, and evaporation. For example, when I put the iron fillings and powdered sulfur into a test tub, I used a magnet to separate the substances. Substances in a compound can be separated by distillation, evaporation, or condensation process because to separate the components will be dif ficult.

Black Death Muslim and Christian Responses

Imagine yourself alone on a street corner, coughing up bloody mucous each time you exhale. You are gasping for a full breath of air, but realizing that is not possible, you give up your fight to stay alive. Youre thinking why is this happening to me? That is how the victims of the Black Death felt. In five short years, the plague killed between 25 and 45% of the populations it encountered. So how different were the Christian and Muslim responses? In 1348 Christians who were followers of Jesus Christ and Muslims who followed the teachings of Muhammad came face to face with the Black Death. In truth, Muslims and Christians responded in many different ways. Even the way the blamed others for the cause of the plague and religious views about the disease were very much different. In a similar manner both religions acted completely out the norm, they basically set aside their spiritual beliefs for a moment. One of the similar responses between the Muslims and Christians were acting out of the ordinary. According to document five both religions were finding non-religious alternatives to prevent the Black Death. In some cases, the Christians would try to sleeping on their backs to prevent the plague, while the Muslims would even avoid going outside. In addition they both drank a solution of Armenian clay to cleanse the body and built fires hoping that this would purify the contaminated air. Based on document nine both the religions united together to pray and they went back to their religious ways. These documents prove that each religion in some cases stepped out their religious backgrounds to try to prevent the Black Death. Religious views played a big part on the different ways the Christians and Muslims responded to the Black Death. The Christians basically thought the plague was their fault. They believe that they’re being punished for their sins they’ve imputed against God. On the other hand the Muslims are taking the plague lightly. They believe that â€Å"a Muslim should devoutly accept the divine act. The Muslims also believe that this occurrence is a blessing from God. In addition document two explains the Black Death Mortality by comparing each religions death rate. The mortality estimate Phillip Ziegler calculated for the Muslims shows that about 33% of the Middle Eastern population have deceased. While the Christian population in Europe mortality rate was only 31%. This document proves that the Muslims population decreased greater than the Christians. During the era of the Black Plague, the Christian community held a lood-thirsty lead hand in the fact of the matter, while the Islam society didn’t blame the epidemic on others and or try to solve the rampant disease with violence. According to document seven the Christians blamed the Jews for causing the Black Death; they believe the Jews poisoned the wells. The Muslims didn’t blame anyone for the occurrence of the Black Death, based on document ten. This proves that the Muslims believed that the plague was meant to happen, like document four said, â€Å"the plague is a blessing from God. †

An intriguing outdoor scene Essay Example | Topics and Well Written Essays - 250 words

An intriguing outdoor scene - Essay Example Dogs and their owners can be seen as well walking or running around for a good exercise. It is a usual meeting place for people which make parks an inherent part of American society. This is why more people and organizations such as Parks for People are calling for the improvement and opening of more parks. â€Å"City parks and open space improve our physical and psychological health, strengthen our communities, and make our cities and neighborhoods more attractive places to live and work† (Sherer, 2006, p.6). These parks contribute more than we realize, even so the national parks that are part of the â€Å"nation’s natural and cultural heritage† (The Untold Stories, 2009, par.2). The vibrancy that is apparent when people flock to the park is testament to its vital role in the community. There is no doubt that parks are ideal places where people mingle and enjoy activities without having to spend a dime. They must be preserved for the continued enjoyment of peopl e and the future generations to

2nd Take Home Exam Essay Example | Topics and Well Written Essays - 500 words

2nd Take Home Exam - Essay Example The doctrine of promissory estoppel is a policy that allows the recovery of a promise made without considering that it will be enforceable (Clarkson 249). The promisee may encounter losses or suffering in the process of ensuring that he gets the promise. This discussion uses a case study where Cato promised Isabella $40,000 after she graduates from State College. Cato fails to honour his promise and claims not to remember promising her the money. Isabella has a right of demanding the money that Cato promised her. The doctrine of promissory estoppel gives her the right to demand that Cato fulfills his promise. Isabella relied on Cato’s promise to complete her university education. The following issues compel Cato to give Isabella the money. First, Cato’s promise was clear and definite, and this means that he knew what he was doing when he promised her the money. Cato wanted Isabella to complete her university education and graduate. Therefore, promised her the money to encourage her to complete her studies. Isabella and Cato understood the promise and thus it is legally binding for him to give her the money. Secondly, Isabella had adequate reasons to rely on the promise to complete her university education. It is necessary to explain that she would not have gone back to school if Cato did not promise her the money. Therefore, she was justified to rely on the promise because she hoped to use the money after gradu ating. Therefore, she perceived the promise to be an economic gate to success. Thirdly, Cato knew that Isabella would rely on his promise to complete her university education. She was sure that Cato would honour his promise and give her the money, and that is why she went to school without doubting Cato’s promise. This doctrine states that the promiser has an obligation of honouring a promise if he knows that the promise will influence the behaviour of the receiver (Clarkson 248). Therefore,

Literary Analysis: The Storm :: essays research papers

The plot of the story "The Storm" by Kate Chopin is a conventional everyday plot. The story would not be so interesting if it weren't for the last line of the story; "So the storm passed and everyone was happy." What did she mean by the closing line? My interpretation of the story is that she meant the rocky part of both Calixta and Alcee's mariage had passed along with the storm. Both Alcee and Calixta cheated on their spouse, however, they both knew that when the stor was over they would return to faithfulness with their mates. Alcee obviously felt regretful, as indicated when the author writes; "It was a loving letter full of tender solicitude." He then went on to say "although he missed them, he was willing to bear the separation a while longer-realizing that their health and pleasure were the first things to be considered." These quotes were taken from the letter Alcee had written to his wife. The storm had passed and it looked as if everyone in Alcee's situation was going to be happy. As for Calixta, she was extremely happy to see her son and husband return home safely, as indicated in the story; "She had clasped Bibi and was kissing him effusively." Calixta then went on to Bobinot and "Felt him to see if he was dry, and seemed to express nothing but satisfaction at their safe return." Calixta had also withstood the storm of her marriage and everyone seemed to be happy too. Alcee and Calixta both seemed to realize they were blessed with loving spouses. In their moment of passion they did not realize how lucky they both were. I feel they both came to grips with the fact that what happened between them was an act of lust and there were no feelings involved. The moment was very arousing to each of them but when the storm was over so was the act of lust and betrayal. My opinion is, this act was going to help both Alcee's and Calixta's marriage rather than hurt it, as long as their respective spouses do not find out what happened during the storm. I bring this up because both guilty parties involved seemed to come away fromthe incident loving their spouses more and realizing that their choice of who to

Beauty Advertisement Analysis Essay

Advertisement or adverts for short is a form of communication for marketing and very often it is used to either coax, encourage and manipulate the audience – spectators, listeners, readers or a group of specified and targeted group to support the product or service at hand. Not only is it common but also convenient and efficient. There are a few approaches a company would want to promote or advertise their product or service. One of the many common and conventional methods of advertising can include billboards, printed flyers, web banners, web popups, magazines, newspapers and even human billboards. Before planning the advert, the product seller should weigh out and consider the three factors that would play a huge role in forming an effective advertisement. The three dimensions are cognitive, affective and behavioral information. Cognitive information would heavily involve about the already existing knowledge. Affective information on the other hand, focuses of the emotions of the individuals and behavioral information focuses on the reaction after reading, hearing or watching the advertisement. There are two ways for the individual to process the information given in the advertisement – systematic and superficial information processing. Systematic information processing is where the information attained is being scrutinized and analyzed while superficial information processing is where the information that is attained requires no in depth reading into the information and just coming up with an impression with the details on the advert. For this advertisement analysis, a beauty advert is selected and it would be critically analyzed to see if the ad is effective and appealing to the masses. To help analyze the advertisement various types of heuristics are being used. The different types of heuristics are, emotions – direct and indirect, attractiveness, familiarity, expertise, message-length, consensus, scarcity and consistency. These will be used to discuss and critique the advertisement. Emotions Emotions are one of the main factors when discussing persuassion. There are two types of emotion – direct and indirect. A direct emotion requires a superficial processing and it is based on a classical conditioning. Hence or this advert that focuses on a beauty product, one of the many common emotion that it would trigger would be curiosity. The indirect emotions that would be triggered from the advert, would be feelings of gratefulness or displeasure. At a glance, the advert may intrigue the audience by providing a more conventional method to resolve the problem at hand for the face or skin while the other feeling that would be evoked in the individual would be doubtful and weariness as there are various beauty products in the market that does not justify the purposes of the product. Attractiveness In general, every individual would be very prone to be attracted to someone who is attractive and likeable. Many adverts would usually have an attractive display or an appealing model to promote their products and services. The audience would be more drawn to the advert despite the product and content that is given. A famous celebrity, who is well known and liked, is being used as a model for the beauty product. A more attractive attribute of an individual would allow a much better start for an interaction between the audience and advertisement. With an appealing model, the beauty product that is being advertised would have a high chance of being likeable and interesting which would decrease the probability for the product to be turned down. Familiarity According to Zajonc (1968) individuals favor products and services that they have been regularly exposed to. Very often, the people or audience would be much more drawn to the product or services that they are able to relate to or if the product is considered to be recognizable to them. When familiarity is established between in advertisement and audience, the audience would feel the sense of belonging (Monin, 2003). Adverts that The advertisement that is used is familiar and also established a bond of belonging with the audience. The word natural and the attractive model that is being used for the advert is familiar to the audience – women – as we have an already formed perception of what beautiful looks like – flawless and natural looking skin. Which is what the model is showing off. That aside, it would also able to identify for individuals who are looking for a solution to their facial problems. Expertise Most often, individuals are easily influenced by the behavior of the experts or those who has the upper hand. The credibility of the source is important when an individual is weighing out their options. The individuals need to be assured that the product or services that is offered is trustworthy and competent as this would allow the individual to form a fast perception of the product or service. Advertisements would usually include pictures of an authority figure or include information that is factual. This advert however does not show or establish any from of specific and clear expertise and authority. Message-Length An advertisement with a long message length would be believed and seen as useful as more information is provided. The informative ad would be more appealing as it offers vital information about the product and services at hand. However this would only be useful and effective if the audience were to use a systematic information processing. For this advert, very short information is given but however, the information is direct and clear. But message length does not play a huge role when an attractive model is being used and it would be able to also entice the same reaction as an advert that is informative. According to Chaiken (1980), individuals would rarely check the validity of the message that is give but instead to the readily information given that would be analyzed. Therefore, in conclusion, information processing plays a major and important role when advertisements are at play. Like information processing, heuristics also influences decision-making. Hence, information processing and heuristics would commonly complement and work together when the audience has to make a choice. Thus when making a choice, the individual has to look for more options and weigh out the advantage and disadvantage, this is where the advertisements would play a major role and what heuristic that is being used would also be taken into consideration.

The Causes and Effects of Smoking Essay - 1028 Words

The Causes and Effects of Smoking Scientists and health officials have been arguing the detrimental effects smoking has on our health for many years. Smoking can lead to serious complications including asthma, pancreas, lung and stomach cancer due to the large number of carcinogens (cancer causing chemicals) and other various substances added to it. It is a health hazard for both smokers and non-smokers and it is especially harmful to unborn babies. Although smokers claim that it helps them to relax and release stress, the negative aspects of the habit take over the positive. As it has been stressed by the scientists and experts, there are some very severe reasons of smoking but its crucial consequences should also be taken into†¦show more content†¦Many people know that smoking is not good for them but they look to identify themselves with something that makes them feel more masculine, feminine or more mature. Another factor is peer pressure which is a powerful influence. Friend are the usual source of the first cigarette and smoking is usually done with friends at parties, or in public places. Young people think that they look like a wimp if they don’t smoke when their peers smoke around them. One last severe cause resulting in smoking addiction psychologically is advertisements. Tobacco companies use images for smoking that are very attractive, adventurous and exciting. The reason why companies use such images is that young people can find their heroes’ image from smoking advertisements so they want to look as impressive as the heroes. The fact is that the companies also play the role of sponsorship in the world of sport, fashion, and art. As a consequence, dangerous products such as cigarettes may seem healthy and trendy. As it is clearly seen smoking cigarettes have several crucial reasons but it shouldn’t be forgotten that smoking has got certain vital results as well. Because tobacco contains many harmful chemicals cigarette smoking causes many dangerous diseases to human beings such as lung cancer, heart disease and teeth decay. Of all the diseases associated with smoking, lung cancer is perhaps the most notorious. Around 90 % of lung cancer is caused by the smoking habit and it is not justShow MoreRelatedCause And Effect Of Smoking1375 Words   |  6 PagesNow we know the most lifesaving way to prevent this is to quit smoking, but did you know people who are exposed to second hand smoking can also get lung cancer, even though a person quit smoking it may have impacted, the cigarette smoke, into someone else’s body. Cigarette smoke is full of cancer-causing material, called carcinogens, this changes the lung tissue right away. Fundamentally, the human body may be able to restore th e damage. 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