How Influenza A causes Epidemics and Pandemics Essay - 1

How Influenza A causes Epidemics and Pandemics - Essay Example The 1918-1919 influenza pandemic which was the most distressful outbreak of influenza in history and considered as one of the most critical disease pandemics ever experienced came about as a result of H1N1 which is a subtype of influenza A virus (Hays, 2005). During this time the pandemic was known to kill over 25 million people globally (Ricks, 2009; p. 34). This essay will address the antigenic drift and the antigenic shift of the virus and how it has affected people globally. Influenza which is commonly referred to as flu is a contagious disease of mammals and birds which is caused by family orthomyxoviridae and RNA viruses. In human beings the signs and symptoms of the disease range from sore throat, severe headache, coughing, fever to fatigue and weakness (Shors, 2009). In more severe scenarios the influenza leads to pneumonia which can be deadly especially in infants and the elderly (Stanberry, 2008). Whilst at times it might be taken for common cold. There are different types of viruses making it to for the pandemic to be contained easily. Flu viruses regularly vary via a method known as antigenic drift. This is the unsystematic accretion of mutations in the HA and to the least degree NA genes which are detected by the system of immune. It is observable in influenza A viruses (Kurstak, 1990). Just like the normal cases of RNA viruses, mutations in the flu viruses take place often due to the replication machinery of the viruses which lacks a proofreading system. Whenever such variations result into mutations in the sites occupied by the antigens of HA or NA that are responsible for the reduction or inhibition of the bond of neutralizing antibodies, the immune system might be avoided by the viruses (Sompayrac, 2002). This procedure gives an explanation of the incident of serial flu epidemics in the course of winter in climatic zones that have temperate conditions and incident of epidemics of varying relentlessness and age groups affect (Betts, Penn

Practice reflections essay Example | Topics and Well Written Essays - 4000 words

Practice reflections - Essay Example An acute ward is a relatively chaotic place with rapid turnover and different levels of psychotic intensity that needs every sane attempt to engage closely with madness. So we can see and hear different behaviors and different stories in a variety of communication patterns. The only thing that an acute nurse maintains is tact and respect to the patient's person to maintain order and avoid abuse in any form. I was struck by the variety of scenes and hope these people will get back to reality and live a normal healthy life. My third placement was at an elderly care where most of them are sick of Alzheimer or Korsakoff syndrome. It was a different scene then. Everything seems to be quite and we seem to get the cooperation of the patients. But we have to make sure we attend to their personal needs and really have to monitor their medications and activities. Alzheimer's disease affects their control for thought, memory, and language and so they have trouble remembering recent events or the names of familiar people or things in their lives. Even the simple tasks of combing their hair or brushing their teeth or even taking a bath are being forgotten by them. They have problems speaking and understanding that they just wander or sit still when their moods are not being aggressive or anxious. I can just smile recalling the repetitive inquiries for my name. I can just smile recalling giving multiple and same line of introductions to these patients. It is like taking care of big babies. The most unpleasant part is cleaning them after they defecate. For sure the smell is not the same as those of the babies. Taking every scene I encountered lightly and with openness of heart and mind will make me want to help them and express forms of sympathy to their medical conditions. I wouldn't want to be a member of these wards, by the grace of God, no. It is too much to bear being a patient and too much emotion of hurt and stress thinking about the provision of care for these patients in the part of the family or relative. Korsakoff's disease level with Alzheimer's in memory loss due to dietary deficiency of Thiamin or Vitamin B1. It creates damage to several brain areas that is critical to memory. All the same they tend to ask your name every encounter. There were numerous staff approaches in maintaining therapeutic treatment and in establishing therapeutic relationship. We have to get their trust and maintain a friendly atmosphere between us so they cannot be too aggressive or violent whenever they dislike something especially with patients placed in the acute wards. I have noted and cared for some patients from the time of their admission until their discharge. In my four weeks assignment placement, I can see that some have come back and was readmitted again. We are being listed for reflections sessions as part of the placement under practice facilitators. At the wards, we also have mentors and been given Practice Based Assignments (PBA) papers. Here we discuss and reflect what we have seen and learned from the ward, an open forum in cases of clarifications of some issues until they get to sign our individual PBA's. For their respective care delivery, we are just observers and taking notes of the medications and techniques on how to inject

Two smillier articles Essay Example | Topics and Well Written Essays - 750 words

Two smillier articles - Essay Example One of the components is the transforming growth factor, also known as TGF B-1. This is an immunosuppressive cytokine that is in the heart, meaning that it is a main protein that functions with relation to helping to fight immunity. It has been found that individuals who have a higher concentration of TGF B-1 in the heart also create atherosclerosis of the coronary arteries. Those who have regular coronary artery disease are not as likely to have the plasma concentration of TGF B-1. Those with both degenerative heart valves and regular coronary valves have a lower amount of TGF B-1, as well as a higher distribution amount of the cytokine throughout the body (Attaran et al, 2010). . The article used (Attaran et al, 2010), conducted a study to determine why those with atherosclerosis of coronary arteries create this specific dysfunction, as opposed to a regular coronary artery disease. 158 patients were studied who were undergoing treatment for coronary artery disease for the first time and which were required to have valve surgery. To conduct this survey, the enzyme inhibitors to the heart were stopped. After this was complete for a period of time, the blood from the heart was collected to determine how the plasma functioned within the heart. Enzyme linked chemicals were used to detect the amount of TGF B-1 that was in each patient’s blood. The results were then compared to the amount of TGF B-1 that was in the normal population and from those who had normal functioning of the heart (Attaran et al, 2010). There were several associations found between the dysfunction of atherosclerosis of coronary arteries and TGF B-1. It was found that those with atherosclerosis of the coronary arteries also suffered from hypertension and myocardial infarction in the past. It was also found that the mean concentration for TGF B-1 was lower than the normal population

Effects of European Expansion in N.America Essay Example for Free

Effects of European Expansion in N.America Essay The news of a New World spread like a forest fire throughout Europe and the race for colonies between Portugal and Spain began. Each country started to conquer the ancient civilizations and exploit the continents raw material. This collision deeply affected all of the Atlantic societies. The conquistadors had a powerful effect that began to create a truly new world in Latin America; the New World would never then be the same after 1492. When Columbus waded shore two ecosystems amalgamated and clashed. When the Europeans arrived, they brought diseases that the Native Americans were not immune to including small pox, measles, bubonic plague, influenza, typhus, diphtheria, yellow fever, malaria and the scarlet fever. Devoid of natural resistance to these diseases, the Native Americans died in great masses. Within fifty years of the Spanish arrival, the population of the Taino natives in Hispaniola dwindled from 1 million people to about 200. In return, the Europeans were infected with syphilis, which they acquired from the Native Americans. Other than disease, the Europeans introduced new crops and plants such as wheat, sugar, rice, coffee, dandelions, daisies, and Kentucky bluegrass. The Europeans also introduced new domestic animals such as horses, cows, and pigs. The introduction of horses caused North American tribes like the Apaches, Sioux, and Blackfoot to adopt these animals, transforming their cultures into highly mobile societies. On the other hand, the Europeans acquired gold and silver as one Aztec described them: They thirsted mightily for gold; they stuffed themselves with it; they starved for it; they lusted for it like pigs. The Europeans were also introduced to new crops such as corn, potatoes, pineapples, tomatoes, tobacco, beans, vanilla, chocolate, and sweet potatoes. Other than material things and disease, the Europeans and the Natives created a new race. This happened when Cortà ©s conquered Mexico and began to encourage intermarriage with the surviving Natives. Although Cortà ©s encouraged intermarriage, he enslaved many of the Native Americans. This created a new and distinctive culture of mestizos. These were some aspects of the collision between the two worldsSpains colonial empire grew swiftly and impressively and as it did it deeply affected all the Atlantic societies. The Spanish success reached France and England causing French and English voyages to be sent in order to get part of this colonial success. In Florida on the borderlands, Spanish  erected forts to protect sea-lanes to the Caribbean, to secure the northern periphery of their New World domain against such encroachments, and to convert Native Americans to Christianity. Unlike the rest of the colonies, the Spanish settlers in New Mexico found little gold fur, but they did discover wealth of souls to be harvested for the Christian religion. The Roman Catholic mission became the central institution in colonial New Mexico until the missionaries efforts to suppress native religious customs provoked a Native uprising called the Pope Rebellion. The Pueblo rebels destroyed every church in the province and killed a score of priests and hundreds of spinach settlers. In California, no serious foreign threat loomed and Spain directed its attention there only belatedly. Rodriguez had explored the California coast in 1542, but he failed to find San Francisco bay or anything else of much interest. For some two centuries after California slumbered undisturbed by European intruders. Then in 1769 Spanish missionaries led by Father Serra found San Diego. Father Serras Franciscan friars toiled with zealous devotion to Christianize 300,000 Native Americans. They gathered the semi-nomadic Native American into fortified missions and taught them horticulture and basic craft. These mission Native Americans adopted Christianity, but they also lost contact with their native cultures and often lost their lives as well, as the white mans diseases doomed these biologically vulnerable peoples. These changes helped create a truly new world in Latin America including the borderlands of Florida, New Mexico, and California; all of which later became part of the United States. In conclusion, the Spanish invaders did indeed kill, enslave, and infect countless natives, but they also built a colossal empire, stretching from California and Florida to Tierra del Fuego. They grafted their culture, laws, religion, and language into a wide array of native-societies, laying the foundations for a score of Spanish-speaking nations.

history of s. africa :: essays research papers fc

INTRODUCTION:   Ã‚  Ã‚  Ã‚  Ã‚   In this paper I will be talking about the history of South Africa and how it was segregated and how apartheid came about and give some acts that were used in order to segregate. I talk about the ANC and how the â€Å"white† government outlawed it. I will also show how the apartheid became a thing of the past and was accepted by the new government in order to make peace and bring unity. CREATION: The National Party went into power in 1948 to strengthen â€Å"white Supremacy†. The National Party made it obvious to the public that it identified this political, economic and social policy with the ideology of ‘apartheid’. They immediately made laws that gave apartheid a legislative reality, which could not be overturned easily. These laws separated whites and blacks and formed the theory that whites should be treated more favorably than blacks.   Ã‚  Ã‚  Ã‚  Ã‚  The Population Act of 1950 was the beginning for separating South Africa’s population into different races. There were only three different races and they were white, coloured and Bantu (black). This act helped pave the way for other acts that were strictly developed to separate whites and blacks. Listed below are just few of the acts:  ·Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  The Group Area Act- mapped out areas that were â€Å"black free†  ·Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Mixed Marriage Act- made it illegal for whites and blacks to marry  ·Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  The Immorality Act- made it illegal for whites and blacks to have sexual relations  ·Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Separate Representation of Voters Amendment Act- made it mandatory that their could only be white representatives when it came to politics The National Party gained a tremendous amount of support from the white electorate. The National Party, which has five-year terms, was re-elected in 1953 and in 1958, which promoted segregation more and more.   Ã‚  Ã‚  Ã‚  Ã‚  While this is going on, the African National Congress (ANC) is fighting for the rights of black people. They were having many boycotts, sit-ins and walking to work instead of having to pay for a ride. While demonstrating in front of a police station in 1960, police fired on demonstrators killing sixty-seven and injuring one hundred eighty-six. A peaceful march took place a while later with 30,000 joined, but led to the arrest of over 18,000 of them. Leaders of the ANC were also arrested, including Nelson Mandela.   Ã‚  Ã‚  Ã‚  Ã‚  Prohibited from operating peacefully in South Africa, the ANC established underground organizations in 1961 to continue their struggle with the government. The ANC bombed police stations and power plants, but was very careful not to take any lives.

External-Internal Factors Paper

There are many internal and external factors that can affect how a business is developed and maintained. Amazon. com has been molded from many of these factors that exist within their business and their macroenvironment. Macroenvironment is defined as the most general elements in the external environment that potentially influence strategic decisions (Bateman & Snell, 2009). Internal business factors can include new entrants, buyers, suppliers, rivals, substitutes and complements, and the competitive environment Amazon is faced with. The macroenvironment introduces the economy, technology, laws and politics, demographics, and social values that may affect Amazon’s progress as a leading, online retail provider. In planning their business, Amazon had to take into account all internal and external factors to avoid catastrophic troubles while beginning their company. The same concept holds true, even today. Internal and external factors affect the planning, organizing, leading, and controlling (four functions of management) functions of management involved in the successful and continual growth of Amazon’s company. Their company began as a planned rival to Google and Microsoft, for lead in the online retail industry. With their original focus, Amazon used four different key values to help their business off-the-ground, and stay focused on their personalized progress. Their ability to zone-in on customers, dynamic pricing, personalized service, and brand variety was their plan for success (Amazon, 2011). It became a primary goal for Amazon to make their customers’ online shopping experience easier and more enjoyable while supplying dynamic pricing options and the convenience of a ‘one-stop’ retail ordering system. The business model of Amazon included selling books, compact discs, movies, electronics, and games. Currently, Amazon has the largest online retail selection because it extends its inventory out to offer home goods, clothing, food, automotive, and jewelry products (Amazon, 2011). Amazon’s website is specifically designed for e-commerce. The features are consumer-friendly and guide the customer through product listings that rival any major department store. Their website allows the recommendation of future product purchases based on consumer shopping/browsing history saved through their advanced customer relationship management (CRM) system. Amazon’s initial desire was to prevent the average consumer from needing to leave the comfort of their own home to accomplish their normal and continual shopping needs. This desire continues to be the driving-point for Amazon’s foundation. Amazon has organized their human resources to provide personalized customer service that readily matches other online retailers. Amazon does not offer in-store customer-service because they are an online business entity; however, they do offer e-mail, phone, and online live-chat customer service support. To enhance Amazon’s website structure, there was need for more consumer options than rival competitors that supported the customer better. Amazon provides other services to include developer, advertising, and self-publishing services. Developer services allow Amazon to use the new idea of incorporating human intelligence tasks into their company’s services, now Amazon is better able to provide for their consumers and their consumer’s business needs. Advertising services enable web developers the use of Amazon’s advertisements on their own websites, for easier customer fulfillment capabilities. Self-publishing services allow on-demand publishing for any novice-to-intermediate non-published authors to display their written content publicly for sale on Amazon. com. To fulfill shipping requirements on retail goods sold, Amazon had to build more than four million warehouses to prevent large amounts of backorders (Amazon, 2011). For dynamic pricing, Amazon conducted real-time price tests to measure out customer responses and adjust prices accordingly for better customer satisfaction. Amazon encourages new retail seller affiliates to sell on their marketplace to expand the purchase options and avenues for its customers. Amazon has remained the leading e-retail provider for the entire world since early 2009 (Stores Magazine, 2010). Amazon hasn’t been affected by new entrants into the retail industry as much as a smaller retail company could. Although new companies do take a slight portion of the industry, Amazon has yet to be financially scathed in a troubling way. In addition to sales, Amazon also provides community support to disaster relief, tools for non profit organizations, and grants for non profit author and publisher groups. This allows the public community to see and understand that Amazon does care for its customers in the furthest sense of the word. Additionally, Amazon is proud to be a business party involved in environmentally aware programs that discern Amazon as an eco-friendly company, by enacting a â€Å"Frustration-Free† packaging model. This makes products easier to open because it uses 100% recyclable cardboard packaging and the product remains the same, just in streamlined packaging (Amazon, 2011). Amazon does its best to render personalized service to their customers. The ‘Recommendations’ feature on their website tracks the purchases each customer makes, so on the next visit to Amazon. com they can see similar products based on previous purchases. Amazon also sends personalized e-mails to customers informing them on new items that fall into their recommended categories. When concerning pricing and branding, Amazon places online customer valued selections, convenience, and good services above pricing (Amazon, 2011). Amazon has instituted several controls to ensure a complex, yet user-friendly website and business. They have supplied their website with enough graphical descriptions and pictures of purchasable goods to ensure more accurate product purchases. By designing a more convenient ‘one-click’ ordering system, the need to re-enter customer payment information had been eliminated. Amazon takes studious care in the ethics, legal, and security issues of their customers. By limiting the amount of internal and external parties that have access to personal customer account information, stating their legal responsibilities for quality of merchandise sold, and educating consumer patrons on security measures, Amazon can better protect Internet purchase transactions. Amazon has expanded to include tools on their website to further assist intermediate consumers. Tools such as the Simple Storage Service (S3), the Elastic Compute Cloud (EC2), and the Mechanical Turk. With the establishment of these services, Amazon can revolutionize their productivity of their storage space, processing power, and non-automated web services by lending space and processing power in their network. This allows Amazon to store, manage, and collect other businesses’ data and information, on their daily business processes and human intelligence tasks, and Amazon takes a percentage of the profit (Amazon, 2011). Whether buying services or goods through Amazon, this combined market strategy allows Amazon to continue to excel at retail leadership and control. References Amazon (2011). Amazon. Retrieved from http://www. amazon. com/ Amazon (2011). Amazon and our planet. Retrieved from http://www. amazon. com/b/ref=gw_m_b_corpres? ie=UTF8&node=13786321 Bateman, T. S. , & Snell, S. A. (2009). Management: Leading and collaborating in a competitive world (8th ed. ). Chapter 1: Managing. Retrieved from https://portal. phoenix. edu/classroom/coursematerials/mgt_330/20110425/. Bateman, T. S. , & Snell, S. A. (2009). Management: Leading and collaborating in a competitive world (8th ed. ). Chapter 2: The External Environment and Organizational Culture. Retrieved from https://portal. phoenix. edu/classroom/coursematerials/mgt_330/20110425/.

Student Life

Your exam will be multiple choice Exam # 1 Introductory Chemistry Be sure to show your set up for all mathematical problems. Your answers must have the correct number of significant digits and the correct units. I. Chemistry is a quantitative science therefore we must make measurements. All measurements have an uncertainty that we need to be aware of in our calculations. A. We need to be able to determine the number of significant figures in a measurement. For the following measurement state the number of significant figures. (4pts) 1. 1. 000 cm 2. 2. 590 x 10-5 m 4 3. . 020 g 4. 1000 cm 2 1 B. We need to be able to add, subtract, multiply, and divide with measurements. Solve the following problems. (4 pts) 1. 3. 02 cm + 5 cm + 0. 002 cm = 8 cm 3. 2. 0 cm x 2. 00 cm x 2. 000 cm = 8. 0 cm3 2. 5. 35 g – 0. 005 g = 5. 35 g 4. 7. 89 g / 5. 2 mL = 1. 5 g/mL B. It is often necessary to convert from one unit to another. This is easily accomplished with the right unit factor. Solve th e following problems. 1. During the last six lunar landings 842 pounds of Moon samples have been collected. What is this mass expressed in kilograms? ( 2. pounds = 1 kilograms) (4 pts) 842 lbs x 1 kg / 2. 2 lbs = 382. 7272727 kg = 380 kg 2. If a 250 mL beaker weighs 95. 4 g, what is the mass in kilograms? (4 pts) 95. 4 g x 1kg / 1000g = 0. 0954 kg = 9. 54 x 10-3 kg 3. If the radius of an oxygen atom is 6. 6 x 10 (5 pts) 6. 6 x 10 –10 dm x 1 m / 10 dm x 109 nm/ 1 m = 6. 6 x 10-2 nm -10 dm, what is the radius in nm? 1 C. Chemists often deal with percent problems. As long as you remember that percent refers to per 100, these problems can be solved. 1. A penny minted after 1982 is composed of copper and zinc only. If a penny has a mass of 2. 07 g and is 2. 50 % copper. What is the mass of zinc in the coin? (5 pts) 2. 507 g x 2. 50/100 = 0. 062675 g of Cu 2. 507 g of penny – 0. 062675 g of Cu = 2. 444325 g = 2. 444 g of Zn (2. 44 g of Zn is correct also) D. Density is a ver y important concept for chemist. The density of a substance can be obtained in a chemistry laboratory. 1. A rubber stopper with a mass of 23. 75 g is dropped in a 50-mL graduated cylinder that has 20. 4 mL of water. After the stopper is dropped in the graduated cylinder, the water level rises to 24. 7 mL. What is the density of the rubber stopper? 5 pts) 2. 375 g / (24. 7 mL – 20. 4 mL) = 5. 523255814 g / mL = 5. 52 g / mL (5. 5 g /mL is accepted) We can make predictions if the density is known. 2. A glass cylinder contains four liquid layers: mercury (d = 13. 6 g/mL), chloroform (d = 1. 49 g/mL), water (d = 1. 00 g/mL), ether (d = 0. 708 g/mL). If a piece of ice (d = 0. 917 g/mL) is dropped into the cylinder, where does it come to rest? Why? (5 pts) The mercury layer will be on the bottom, then the chloroform, then the water, and finally the ether. The ice will sink in the ether layer and float on top of the water layer. If the density is know, we can we can find the mass of a given volume or the volume of a given mass. 3. The density of aluminum is 2. 70 g/mL. What volume will 250 g of Al occupy? What is the mass of a piece of aluminum with a volume of 250 mL? (6 pts) 250 g of Al x 1 mL / 2. 70 g = 92. 59259259 mL = 93 mL 250 mL of Al x 2. 70 g / 1 mL = 675 g = 680 g 2 Using the density value we can indirectly obtain distances that are too small to measure directly. 4. A sample of aluminum foil has a length of 10. 0 cm and a width of 5. 7 cm. If the aluminum foil weighs 0. 234 g, what is the thickness of the aluminum foil? Remember that the density of aluminum is 2. 70 g/mL. (6 pts) Volume of Al = length x width x thickness = mass / density 0. 234 g x 1 mL / 2. 70 g = 0. 0866666666 mL 0. 086666666 mL / 10. 0 cm x 5. 7 cm = 0. 001520467 cm = 1. 5 x 10 –3 cm E. Heat and temperature are two very important concepts. 1. In your own words, please state the difference between heat and temperature. What is a common unit of each? (5 pts) Heat measures the total energy of a sample and temperature measure the intensity of heat or the average heat of a sample. A common unit of heat is a calorie and a common unit of temperature is Kelvin. It is important to be able to convert from one temperature unit to another. 2. Aluminum melts at 1220 F. (You can see why aluminum is not a liquid at room temperature) What is the melting point of aluminum in degree Celsius ( C) and in Kelvin o C (6 pts) (K)? (oF – 32 oF) x 100 oC = 180 oF (1220 oF – 32)(100 / 180) = 660 oC 660 oC + 273 = 933 K o o 3. Give the ions present and their relative numbers in potassium sulfate. a) b) c) d) e) 1K+ and 1 SO42K+ and 1 SO321K+ and 2 SO422K+ and 1 SO423K+ and 1 SO43- 3 4. How many cm2 are in an area of 4. 21in2? a. b. c. d. e. 10. 7 cm2 114 cm2 27. cm2 1. 66 cm2 1. 14 cm2 5. In performing a multistep calculation, when should you round off the answer in the calculator display? (5 pts) In a multistep calculation you should round off the answer at the end of the calculation E. Matter and Energy. 1. We learned four terms in chapter 4, heterogeneous mixture, homogeneous mixture, compound, and element. Please an example of each. (8 pts) An example of a heterogeneous mixture is the earth’s crust. A heterogeneous mixture can be separated into pure substances by physical methods. An example of a homogeneous mixture is salt water. The properties of a homogeneous mixture constant for a given sample. An example of a compound is NaCl. A compound can be broken down into elements by ordinary chemical reactions. An example of an element is Na. An element is a substance that can not be broken down further by a chemical reaction. 2. Match Symbols and Names (10 pts) 1. sodium 2. iron 3. carbon 4. nitrogen 5. phosphorous d c e b a a. P b. N c. Fe d. Na e. C 4 1. Cl 2. Ce 3. Cu 4. Co 5. Ca e c b d a a. Calcium b. Copper c. Cesium d. Cobalt e. Chlorine 3. Give an example for each of the following terms: (8 pts) a. hysical property – Appearance, melting point, boiling point, density, heat and electrical conductivity, solubility, and physical state under normal conditions are all examples of physical properties. b. chemical property – A chemical property of a substance describes its chemical reactions with other substances. The chemical property of sodium states that sodium will react with water to form hydrog en gas. c. physical change – A physical change include changing shape, volume, or physical state. For example when water changes to ice. d. chemical change – A chemical change always involves the formation of a new substance. Gas bubbles from the reaction of calcium with water. Fill in the blanks of the following table Symbol number of protons number of neutrons number of electrons mass number 37 Cl17 20 18 48 Cr3+ 24 24 21 24 Mg 12 12 12 37 48 24 Might not be on test. Ask teacher. Chlorine has two stable isotopes with masses of 34. 97 amu and 36. 97 amu. What is the relative abundance of the two isotopes? a. b. c. d. e. 50. 00% 35Cl and 50. 00 % 37Cl 35. 45% 35Cl and 64. 55 % 37Cl 64. 55% 35Cl and 35. 45% 37Cl 24. 23% 35Cl and 75. 77 % 37Cl 75. 77 % 35Cl and 24. 23 % 37Cl 5 Student Life Your exam will be multiple choice Exam # 1 Introductory Chemistry Be sure to show your set up for all mathematical problems. Your answers must have the correct number of significant digits and the correct units. I. Chemistry is a quantitative science therefore we must make measurements. All measurements have an uncertainty that we need to be aware of in our calculations. A. We need to be able to determine the number of significant figures in a measurement. For the following measurement state the number of significant figures. (4pts) 1. 1. 000 cm 2. 2. 590 x 10-5 m 4 3. . 020 g 4. 1000 cm 2 1 B. We need to be able to add, subtract, multiply, and divide with measurements. Solve the following problems. (4 pts) 1. 3. 02 cm + 5 cm + 0. 002 cm = 8 cm 3. 2. 0 cm x 2. 00 cm x 2. 000 cm = 8. 0 cm3 2. 5. 35 g – 0. 005 g = 5. 35 g 4. 7. 89 g / 5. 2 mL = 1. 5 g/mL B. It is often necessary to convert from one unit to another. This is easily accomplished with the right unit factor. Solve th e following problems. 1. During the last six lunar landings 842 pounds of Moon samples have been collected. What is this mass expressed in kilograms? ( 2. pounds = 1 kilograms) (4 pts) 842 lbs x 1 kg / 2. 2 lbs = 382. 7272727 kg = 380 kg 2. If a 250 mL beaker weighs 95. 4 g, what is the mass in kilograms? (4 pts) 95. 4 g x 1kg / 1000g = 0. 0954 kg = 9. 54 x 10-3 kg 3. If the radius of an oxygen atom is 6. 6 x 10 (5 pts) 6. 6 x 10 –10 dm x 1 m / 10 dm x 109 nm/ 1 m = 6. 6 x 10-2 nm -10 dm, what is the radius in nm? 1 C. Chemists often deal with percent problems. As long as you remember that percent refers to per 100, these problems can be solved. 1. A penny minted after 1982 is composed of copper and zinc only. If a penny has a mass of 2. 07 g and is 2. 50 % copper. What is the mass of zinc in the coin? (5 pts) 2. 507 g x 2. 50/100 = 0. 062675 g of Cu 2. 507 g of penny – 0. 062675 g of Cu = 2. 444325 g = 2. 444 g of Zn (2. 44 g of Zn is correct also) D. Density is a ver y important concept for chemist. The density of a substance can be obtained in a chemistry laboratory. 1. A rubber stopper with a mass of 23. 75 g is dropped in a 50-mL graduated cylinder that has 20. 4 mL of water. After the stopper is dropped in the graduated cylinder, the water level rises to 24. 7 mL. What is the density of the rubber stopper? 5 pts) 2. 375 g / (24. 7 mL – 20. 4 mL) = 5. 523255814 g / mL = 5. 52 g / mL (5. 5 g /mL is accepted) We can make predictions if the density is known. 2. A glass cylinder contains four liquid layers: mercury (d = 13. 6 g/mL), chloroform (d = 1. 49 g/mL), water (d = 1. 00 g/mL), ether (d = 0. 708 g/mL). If a piece of ice (d = 0. 917 g/mL) is dropped into the cylinder, where does it come to rest? Why? (5 pts) The mercury layer will be on the bottom, then the chloroform, then the water, and finally the ether. The ice will sink in the ether layer and float on top of the water layer. If the density is know, we can we can find the mass of a given volume or the volume of a given mass. 3. The density of aluminum is 2. 70 g/mL. What volume will 250 g of Al occupy? What is the mass of a piece of aluminum with a volume of 250 mL? (6 pts) 250 g of Al x 1 mL / 2. 70 g = 92. 59259259 mL = 93 mL 250 mL of Al x 2. 70 g / 1 mL = 675 g = 680 g 2 Using the density value we can indirectly obtain distances that are too small to measure directly. 4. A sample of aluminum foil has a length of 10. 0 cm and a width of 5. 7 cm. If the aluminum foil weighs 0. 234 g, what is the thickness of the aluminum foil? Remember that the density of aluminum is 2. 70 g/mL. (6 pts) Volume of Al = length x width x thickness = mass / density 0. 234 g x 1 mL / 2. 70 g = 0. 0866666666 mL 0. 086666666 mL / 10. 0 cm x 5. 7 cm = 0. 001520467 cm = 1. 5 x 10 –3 cm E. Heat and temperature are two very important concepts. 1. In your own words, please state the difference between heat and temperature. What is a common unit of each? (5 pts) Heat measures the total energy of a sample and temperature measure the intensity of heat or the average heat of a sample. A common unit of heat is a calorie and a common unit of temperature is Kelvin. It is important to be able to convert from one temperature unit to another. 2. Aluminum melts at 1220 F. (You can see why aluminum is not a liquid at room temperature) What is the melting point of aluminum in degree Celsius ( C) and in Kelvin o C (6 pts) (K)? (oF – 32 oF) x 100 oC = 180 oF (1220 oF – 32)(100 / 180) = 660 oC 660 oC + 273 = 933 K o o 3. Give the ions present and their relative numbers in potassium sulfate. a) b) c) d) e) 1K+ and 1 SO42K+ and 1 SO321K+ and 2 SO422K+ and 1 SO423K+ and 1 SO43- 3 4. How many cm2 are in an area of 4. 21in2? a. b. c. d. e. 10. 7 cm2 114 cm2 27. cm2 1. 66 cm2 1. 14 cm2 5. In performing a multistep calculation, when should you round off the answer in the calculator display? (5 pts) In a multistep calculation you should round off the answer at the end of the calculation E. Matter and Energy. 1. We learned four terms in chapter 4, heterogeneous mixture, homogeneous mixture, compound, and element. Please an example of each. (8 pts) An example of a heterogeneous mixture is the earth’s crust. A heterogeneous mixture can be separated into pure substances by physical methods. An example of a homogeneous mixture is salt water. The properties of a homogeneous mixture constant for a given sample. An example of a compound is NaCl. A compound can be broken down into elements by ordinary chemical reactions. An example of an element is Na. An element is a substance that can not be broken down further by a chemical reaction. 2. Match Symbols and Names (10 pts) 1. sodium 2. iron 3. carbon 4. nitrogen 5. phosphorous d c e b a a. P b. N c. Fe d. Na e. C 4 1. Cl 2. Ce 3. Cu 4. Co 5. Ca e c b d a a. Calcium b. Copper c. Cesium d. Cobalt e. Chlorine 3. Give an example for each of the following terms: (8 pts) a. hysical property – Appearance, melting point, boiling point, density, heat and electrical conductivity, solubility, and physical state under normal conditions are all examples of physical properties. b. chemical property – A chemical property of a substance describes its chemical reactions with other substances. The chemical property of sodium states that sodium will react with water to form hydrog en gas. c. physical change – A physical change include changing shape, volume, or physical state. For example when water changes to ice. d. chemical change – A chemical change always involves the formation of a new substance. Gas bubbles from the reaction of calcium with water. Fill in the blanks of the following table Symbol number of protons number of neutrons number of electrons mass number 37 Cl17 20 18 48 Cr3+ 24 24 21 24 Mg 12 12 12 37 48 24 Might not be on test. Ask teacher. Chlorine has two stable isotopes with masses of 34. 97 amu and 36. 97 amu. What is the relative abundance of the two isotopes? a. b. c. d. e. 50. 00% 35Cl and 50. 00 % 37Cl 35. 45% 35Cl and 64. 55 % 37Cl 64. 55% 35Cl and 35. 45% 37Cl 24. 23% 35Cl and 75. 77 % 37Cl 75. 77 % 35Cl and 24. 23 % 37Cl 5