New England DBQ Essay Example

New England DBQ Essay Even though the New England and Chesapeake regions were settled by people from the same country, they developed into very different societies because their original settlers were tremendously diverse. The Chesapeake region inclined more towards work and business, while the New England region was very family oriented. While the emigrants to the Chesapeake region came for financial reasons, the Puritans came to New England to run from religious persecution. And finally, the Chesapeake area was very unstable and under conflict while the North maintained law and order. Emigrants to the Chesapeake settled primarily for financial reasons, and the Puritans settled the New England area for religious matters. As we know, the Puritans originally settled in the Mass. Bay Area Colony and believed they were on a mission from God. God almighty in his most holy and wise providence hath disposedwe must knit together in this and work as one man (doc. A). The Puritans believed that they were an examp le for the rest of the world and that the eyes of all people are upon us. Emigrants to the Chesapeake region moved for financial reasons, most likely being young, indentured servants. Some of them believed that there was a treasure of gold in the colonies. They dug gold, washed gold, refined old, and loaded gold (doc. F). The emigrants were usually young, around ages 19-30 (doc. C) looking for a means of financial gain. Moving on, the Puritans of the New England area usually came to the New World with their entire families, while emigrants to the Chesapeake region were single, mostly young men. The Puritans hoped to establish communities in New England, thus they brought along their whole family. Joseph Hull, a minister, brought along his wife, 7 kids, and servants to the New World (doc. B). These people literally dug out their roots and planted them in the New World. On the other hand, emigrants to the Chesapeake region came to the bi

10 Facts About the Geography of Reykjavik, Iceland

10 Facts About the Geography of Reykjavik, Iceland Reykjavik is the capital city of Iceland. It is also the largest city in that country and with its latitude of 64Ëš08N, it is the worlds northernmost capital city for an independent nation. Reykjavik has a population of 120,165 people (2008 estimate) and its metropolitan area or the Greater Reykjavik area has a population of 201,847 people. It is the only metropolitan area in Iceland. Reykjavik is known as being Icelands commercial, governmental and cultural center. It is also known as being the worlds Greenest City for its use of hydro and geothermal power. What to Know About Iceland The following is a list of ten more facts to know about Reykjavik, Iceland: 1) Reykjavik is believed to have been the first permanent settlement in Iceland. It was established in 870 C.E. by Ingà ³lfr Arnarson. The original name of the settlement was Reykjarvik which loosely translated to the Bay of Smokes due to the regions hot springs. The additional r in the citys name was gone by 1300. 2) In the 19th century Icelanders began to push for independence from Denmark and because Reykjavik was the regions only city, it became the center of these ideas. In 1874 Iceland was given its first constitution, which gave it some legislative power. In 1904, executive power was given to Iceland and Reykjavik became the location of the minister for Iceland. 3) During the 1920s and 1930s, Reykjavik became the center of Icelands fishing industry, especially that of salt-cod. During World War II, the allies occupied the city, despite the German occupation of Denmark in April 1940. Throughout the war, both American and British soldiers built bases in Reykjavik. In 1944 the Republic of Iceland was founded and Reykjavik was named as its capital. 4) Following WWII and Icelands independence, Reykjavik began to grow considerably. People began to move to the city from Icelands rural areas as jobs increased in the city and agriculture became less important to the country. Today, finance and information technology are important sectors of Reykjaviks employment. 5) Reykjavik is the economic center of Iceland and Borgartà ºn is the financial center of the city. There are over 20 major companies in the city and there are three international firms with headquarters there. As a result of its economic growth, Reykjaviks construction sector is also growing. 6) Reykjavik is considered a multicultural city and in 2009, foreign-born peoples made up 8% of the citys population. The most common groups of ethnic minorities are Poles, Filipinos, and Danes. 7) The city of Reykjavik is located in southwest Iceland at only two degrees south of the Arctic Circle. As a result, the city gets only four hours of sunlight on its shortest day in the winter and during the summer it receives almost 24 hours of daylight. 8) Reykjavik is located on Icelands coast so the citys topography consists of peninsulas and coves. It also has some islands that were once connected to the mainland during the last ice age about 10,000 years ago. The city is spread out over a large distance with an area of 106 square miles (274 sq km) and as a result, it has a low population density. 9) Reykjavik, like most of Iceland, is geologically active and earthquakes are not uncommon in the city. In addition, there is volcanic activity nearby as well as hot springs. The city is also powered by hydro and geothermal energy. 10) Although Reykjavik is located near the Arctic Circle it has a much milder climate than other cities at the same latitude due to its coastal location and the nearby presence of the Gulf Stream. Summers in Reykjavik are cool while winters are cold. The average January low temperature is 26.6ËšF (-3ËšC) while the average July high temperature is 56ËšF (13ËšC) and it receives about 31.5 inches (798 mm) of precipitation per year. Because of its coastal location, Reykjavik is also usually very windy year round. Sources:Wikipedia.com. Reykjavik - Wikipedia, the Free Encyclopedia. Retrieved from: http://en.wikipedia.org/wiki/Reykjav%C3%ADk

Arnolds Expedition to Quebec during the American Revolution

Arnolds Expedition to Quebec during the American Revolution Arnold Expedition - Conflict Dates: The Arnold Expedition took place from September to November 1775 during the American Revolution (1775-1783). Arnold Expedition - Army Commander: Colonel Benedict Arnold1,100 men Arnold Expedition - Background: Following their capture of Fort Ticonderoga in May 1775, Colonels Benedict Arnold and Ethan Allen approached the Second Continental Congress with arguments in favor of invading Canada.   They felt this a prudent course as all of Quebec was held by around 600 regulars and intelligence indicated that the French-speaking population would be favorably inclined towards the Americans.   Additionally, they pointed out that Canada could serve as a platform for British operations down Lake Champlain and the Hudson Valley.   These arguments were initially rebuffed as Congress expressed concern over angering the residents of Quebec.   As the military situation shifted that summer, this decision was reversed and Congress directed Major General Philip Schuyler of New York to advance north via the Lake Champlain-Richelieu River corridor. Unhappy that he had not been chosen to lead the invasion, Arnold traveled north to Boston and met with General George Washington whose army was conducting a siege of the city.   During their meeting, Arnold proposed taking a second invasion force north via Maines Kennebec River, Lake Mà ©gantic, and Chaudià ¨re River.   This would then unite with Schuyler for a combined assault on Quebec City.   Corresponding with Schuyler, Washington obtained the New Yorkers agreement with Arnolds proposal and gave the colonel permission to commence planning the operation.   To transport the expedition, Reuben Colburn was contracted to build a fleet of bateaux (shallow draft boats) in Maine. Arnold Expedition - Preparations: For the expedition, Arnold selected a force of 750 volunteers which was divided into two battalions led by Lieutenant Colonels Roger Enos and Christopher Greene.   This was augmented by companies of riflemen led by Lieutenant Colonel Daniel Morgan.   Numbering around 1,100 men, Arnold expected his command to be able to cover the 180 miles from Fort Western (Augusta, ME) to Quebec in around twenty days.   This estimate was based on a rough map of the route developed by Captain  John Montresor in 1760/61.   Though Montresor was a skilled military engineer, his map lacked detail and possessed inaccuracies.   Having gathered supplies, Arnolds command moved to Newburyport, MA where it embarked for the Kennebec River on September 19.   Ascending the river, it arrived at Colburns home in Gardiner the next day. Coming ashore, Arnold was disappointed in the bateaux constructed by Colburns men.   Smaller than anticipated, they were also built from green wood as sufficient dried pine had not been available.   Briefly pausing to permit additional bateaux to be assembled, Arnold dispatched parties north to Forts Western and Halifax.   Moving upstream, the bulk of the expedition reached Fort Western by September 23.   Departing two days later, Morgans men took the lead while Colburn followed the expedition with a group of boatwrights to make repairs as necessary.   Though the force reached the last settlement on the Kennebec,  Norridgewock Falls, on October 2,  problems were already widespread as the green wood led to the bateaux leaking badly which in turn destroyed food and supplies.   Similarly, worsening weather caused health issues throughout the expedition.   Ã‚         Arnold Expedition - Trouble in the Wilderness: Forced to portage the bateaux around Norridgewock Falls, the expedition was delayed for a week due to the effort required to move the boats overland.   Pushing on, Arnold and his men entered the Dead River before arriving at the Great Carrying Place on October 11.   This portage around an unnavigable stretch of the river stretched for twelve miles and included an elevation gain of around 1,000 feet.   Progress continued to be slow and supplies became an increasing concern.   Returning to the river on October 16, the expedition, with Morgans men in the lead, battled heavy rains and a strong current as it pushed upstream.   A week later, disaster struck when several bateaux carrying provisions overturned.   Calling a council of war, Arnold decided to press on and dispatched a small force north to attempt to secure supplies in Canada.   Also, the sick and injured were sent south. Trailing behind Morgan, Greenes and Enos battalions increasingly suffered from a lack of provisions and were reduced to eating shoe leather and candle wax.   While Greenes men resolved to continue, Enos captains voted to turn back.   As a result, around 450 men departed the expedition.   Nearing the height of land, the weaknesses of Montresors maps became apparent and the lead elements of the column repeatedly became lost.   After several missteps, Arnold finally reached  Lake Mà ©gantic on October 27 and began descending the upper Chaudià ¨re a day later.   Having achieved this goal, a scout was sent back to Greene with directions through the region.   These proved inaccurate and a further two days were lost.    Arnold Expedition - Final Miles: Encountering the local population on October 30, Arnold distributed a letter from Washington asking them to assist the expedition.   Joined on the river by the bulk of his force the next day, he received food and care for his sick from those in the area.   Meeting Jacques Parent, a resident of Pointe-Levi, Arnold learned that the British were aware of his approach and had ordered all boats on the south bank of the St. Lawrence River to be destroyed.   Moving down the  Chaudià ¨re, the Americans arrived at Pointe-Levi, across from Quebec City, on November 9.   Of Arnolds original force of 1,100 men, around 600 remained.   Though he had believed the route to be around 180 miles, in actuality it had totaled approximately 350. Arnold Expedition - Aftermath: Concentrating his force at the mill of John Halstead, a New Jersey-born businessman, Arnold began making plans for crossing the St. Lawrence.   Purchasing canoes from the locals, the Americans crossed on the night of November 13/14 and were successful in evading two British warships in the river.   Approaching the city on November 14, Arnold demanded its garrison surrender.   Leading a force consisting of around 1,050 men, many of which were raw militia, Lieutenant Colonel Allen Maclean refused.   Short on supplies, with his men in poor condition, and lacking artillery, Arnold withdrew to  Pointe-aux-Trembles five days later to await reinforcements. On December 3, Brigadier General Richard Montgomery, who had replaced an ill Schuyler, arrived with around 300 men.   Though he had moved up Lake Champlain with a larger force and captured Fort St. Jean on the  Richelieu River, Montgomery had been forced to leave many of his men as garrisons at Montreal and elsewhere along the route north.   Assessing the situation, the two American commanders decided to assault Quebec City on the night of December 30/31.   Moving forward, they were repelled with heavy losses in the Battle of Quebec and Montgomery was killed.   Rallying the remaining troops, Arnold attempted to lay siege to the city. This proved increasingly ineffective as men began to depart with the expiration of their enlistments. Though he was reinforced, Arnold was compelled to retreat following the arrival of 4,000 British troops under Major General John Burgoyne. After being beaten at Trois-Rivià ¨res on June 8, 1776, the Americans were forced to retreat back into N ew York, ending the invasion of Canada.      Ã‚         Selected Sources: Arnold Expedition Historical SocietyArnolds Expedition to QuebecMaine Encyclopedia: Arnold Expedition

Nmgmt Essay Example | Topics and Well Written Essays - 750 words

Nmgmt - Essay Example geting but ‘orthodox’ planning approaches are insufficient for handling large-scale changes as opposed to incremental changes, according to Kotter and Cohen (2002). Significant structural changes had begun to take place in 1994 because of the arrival of free trade. Free trade in the UK’s market meant that foreign competition was coming and was providing local businesses with an opportunity to expand by means of acquisition. Charles Berry has quoted the response of his organization to the change. Even after everyone had agreed to a mutual point and the agreed suggestions were documented in a report, no real progress was made. Hence, all the planning efforts went down the drains because they were not put to work. Most of the industries are designed for incremental changes and commonly everyone associated knows about their business in some detail. Planning helps with such incremental changes where everyone is aware of the little details. However it is inadequate for managing large-scale changes. With non-incremental change, the analysis is often based on unclear assumptions because extrapolations from previous trends may be misleading. Charles Berry explains how his organization considered seven alternatives in an effort to evaluate the situation. In measurable terms, these included sales turnover, the number of employees, potential customer market, core business, competitors, beliefs and the proposed action steps. All the options were documented precisely and several meetings were conducted in order to visualize the propositions in a way that materialized the visions into a near reality. This provided a direction for the attainment of the vision and things got less vague. Hence, the approach , involving seeing, feeling, and changing, was particularly geared towards painting the picture or visualizing the future. There are four main elements involved in successful changes that occur on a large scale. These include plans, budgets, strategies, and visions.

Annual report for Intercontinental Hotels Group plc for the year ended Essay

Annual report for Intercontinental Hotels Group plc for the year ended 31 December 2011 - Essay Example $ in mn Revenue and Profits 2011 2010 % Inc. Sales 1768 1628 8.60 Operating profit 559 444 25.90 Exceptional items 35 15 133.33 Total operating profit 594 459 29.41 Profit before exceptional items 497 382 30.10 Tax -120 -98 22.45 Profit from continuing operations 377 284 32.75 Exceptional items 83 7 1085.71 Net profit including exceptional items 460 291 58.08 Financial position Good will and other intangible assets 400 358 11.73 Other non-current assets 1990 1952 1.95 Total non-current assets 2390 2310 3.46 Current assets 578 466 24.03 Total assets 2968 2776 6.92 Total current liabilities 860 921 -6.62 Total non-current liabilities 1553 1564 -0.70 Total liabilities 2413 2485 -2.90 Shareholders’ funds 555 291 90.72 Total capital employed 2968 2776 6.92 No. of shares 289472651 Shares issued during the year 1075438 Total number of shares 290548089 289472651 Financial Ratios Earnings per share (EPS) Profit from continuing operations/ 1.30 0.98 Number of shares outstanding ROCE Net income/Capital employed 12.70% 10.23% Operating profit margin (Excl. exceptional items) Operating profit /Capital employed 31.62% 27.27% Operating profit margin (Incl. exceptional items) Total Operating profit /Capital employed 33.60% 28.19% Net profit margin after tax (Excl. exceptional items) Net profit after tax excl. excep. items/Capital employed 21.32% 17.44% Net profit margin after tax (Incl. excep. items) Net profit after tax incl. excep. items/Capital employed 26.02% 17.87% Asset turnover Total sales/Total assets 0.60 0.59 Current ratio Current assets/Current liabilities 0.67 0.51 Acid test ratio Quick assets/Current liabilities 0.64 0.49 Receivables collection period Debtors (Trade and other receivables) 369.00 371.00 Total debtors/Sales x 365 76.18 83.18 Payables payment period Creditors (Trade and other payables) 707.00 722.00 Total purchases or cost of sales 771.00 753.00 Creditors/Cost of sales x 365 334.70 349.97 Gearing Total debt/Total equity 4.35 8.54 Interest cove r Interest charges (Interest) 64.00 64.00 Earnings before interest and tax (EBIT)/Interest 5.89 4.44 Price earnings ratio Share price as on 31 December ?11.57 ?12.43 Share price / EPS 8.92 12.67 Dividend cover Dividend paid to shareholders 148 121 Dividend paid/Net income 2.55 2.35 Revenue per available room Revenue per available room is up by 6.2% Revenue per room has been calculated by the company by dividing the total room revenue by the number of room nights available. Analysis of the financial performance and position InterContinental Hotels Group is a global hotel company, operating seven highly-respected brands internationally. Total number of rooms operating under IHG brands is 658,348 (4,480 hotels). IHG’s portfolio of brands includes Inter Continental Hotels & Resorts, Crowne Plaza Hotels & Resorts, Hotel Indigo, The Holiday Inn, Staybridge Suites and Candlewood Suites. The performance of the management should be viewed in relation to the industry for the purpose of meaningful evaluation. The revenue per availab

Low ÃŽ- Irradiation Doses on Saccharomyces Cerevisiae

Low Î’- Irradiation Doses on Saccharomyces Cerevisiae RESULTS OF LOW ÃŽ ²- IRRADIATION DOSES ON SACCHAROMYCES CEREVISIAE FERMETATION PROCESS LetiÃ…Â £ia OPREAN1, Dan CHICEA2, EnikÅ‘ GASPAR, Ecaterina LENGYEL Abstract Four different strains of Saccharomyces cerevisiae yeast samples were irradiated using a 90Sr nuclear source. The results of this ongoing study reveal that the small irradiation doses used in the work reported here produce measurable changes in the fermentation parameters and in the lipid and phospholipid levels. Key words: Saccharomyces cerevisiae, small doses, fermentation. 1. INTRODUCTION Yeasts are a growth form of eukaryotic microorganisms classified in the kingdom Fungi. Approximately 1500 species of yeasts have been described, most of which reproduce asexually by budding, although in a few cases by binary fission. Yeasts are unicellular, although some species with yeast forms may become multicellular through the formation of a string of connected budding cells known as pseudohyphae, or true hyphae as seen in most moulds. Industrial yeasts are of special interest for microbiology and biotechnology because they have a big content of lipids and phospholipids that are currently used in naturist products preparation. Nowadays, comprehensive research is being done with respect to the methods of obtaining lipids and phospholipids from lipid biocomponents, in order to identify new methods for obtaining liposomal substances, needed by the pharmaceutical, cosmetic and medical industry. At present, egg lecithin is being used instead but the use of this source has several drawbacks, such as for example the fact that it oxidizes easily. Eukaryotes (yeasts, fungi, algae) are the main microorganisms that produce lipids and phospholipids. Of great interest to microbiology and biotechnology are the researches conducted in the field of phospholipids synthesis, of obtaining phospholipids from microorganisms and of optimizing culture media for their cultivation. During the last decades, ionizing radiations have been investigated to determine their influence on living organisms. Radionuclides are released into the environment from various sources: nuclear accidents, as planned discharges from the nuclear power industry, disposal of radioactive waste, medical use, nuclear weapons development or recycling. Ionizing radiations are able to cause toxically and genetic effects on organisms, because radionuclides do accumulate in biotic and abiotic components of the environment [1]. Nuclear radiation can stimulate morphogenetic changes manifest in the early development stages [2], [3]. Nuclear radiation can directly disturb metabolic processes, such as photosynthesis, growth, plant respiration, active transport as well as ionic balance and enzyme synthesis [4]. The literature reveals that low doses of ionizing radiations can stimulate cell proliferation [5], [6]. In this study, we investigated the low doses of beta radiation influence on the four Sa ccharomyces cerevisia strings, mainly the influence on the fermentation process. The details of the samples irradiation and fermentation analysis are presented in sections 2 and 3. 2. SAMPLE IRRADIATION The samples were irradiated one at a time in an irradiation chamber that was build for this purpose. The hole in the upper part fits a glass tube than can be easily inserted and extracted. The tube is used to place the sample in the proximity of the beta irradiation source. The schematic of the irradiation chamber is presented in Fig.1. The dose debit through the glass tube, in the very location where the yest samples were placed one by one, was measured using a RFT KD27012 dosimeter with an ion chamber. Fig. 1 The beta-irradiation chamber The ÃŽ ²- source was 90Sr and decays by the scheme: (1) having Eà ¯Ã‚ Ã‚ ¢=546 keV, with a branching ratio of 100% [7]. The daughter nucleus, 90Y, is unstable as well. It decays by the scheme: (2) with the energies, branching ratios and half-lives presented in Table 1. Table 1 The ÃŽ ² energies, branching ratios and half-lives of the 90Y [7]. Eà ¯Ã‚ Ã‚ ¢ (keV) Ià ¯Ã‚ Ã‚ ¢ (%) Half-life, hours 93.83 0.0000014 64.00 519.39 0.0115 64.00 642.77 0.0018 3.19 2280.1 99.9885 64.00 Four strings of Saccharomyces cerevisiae yeast samples were used. The first string, labeled SCP, was separated from Turkish yeast having the trademark Pakmaya. The second string was labeled SCO and was separated from yeast having the trademark Dr.Oetker. The third string, labeled SCSL, was separated from French yeast having the trademark Saff Levure. The fourth string, labeled SCH, was separated from Dutch yeast having the trademark Hollandia. Two sample of each string were prepared, having a suffix 1, for the control, nonirradiated samples and 2 for the irradiated samples. The yeast sample type, irradiation time and irradiation dosis are presented in Table 2 Table 2 The sample type, irradiation time and irradiation dosis Nr. Sample Irradiation time (h) Irradiation Dosis, (Gray) 1 SCP1 0 0 2 SCP2 5 12 3 SCO1 0 0 4 SCO2 5 12 5 SCSF1 0 0 6 SCSF2 5 12 7 SCH1 0 0 8 SCH2 5 12 3. Fermentation details Both the control and the irradiated samples were cultivated in Malt Agar. Malt Agar is used for isolating and cultivating yeasts and molds from food and for cultivating yeast and mold stock cultures [8], [9]. Malt Agar contains malt extract which provides the carbon, protein and nutrient sources required for the growth of microorganisms. Agar is the solidifying agent. The acidic pH of Malt Agar allows for optimal growth of molds and yeasts while restricting bacterial growth. The eight samples described above were subject to a fermentation process conducted in identical conditions, in an ECONOMY 20 fermenter. The temperature was maintained constant at 28 °C. The acidity was maintained at pH=5.8. The maltasic activity (which is defined as catalysis of the hydrolysis of maltose by an alpha-D-glucosidase-type action) and the CO2 emission were monitored for 96 hours [10]. The results of the fermentation activity, measured as CO2 emission and the maltasic activity measured at 24 hours interval are presented in Table 3. The CO2 emission at 24 hours interval is presented in Fig. 2 and the maltasic activity in Fig. 3. Table 3 Results of the fermentation activity Nr. crt. Yeast string CO2-24h maltasic activity 24 h CO2-48h maltasic activity 48 h CO2-72h maltasic activity 72 h CO2-96h maltasic activity 96 h 1 SCP1 0.5 780 1.5 810 1.3 800 0.3 760 2 SCP2 0.8 1220 1.6 1240 1.5 1200 0.5 1200 3 SCO1 0.7 840 1.3 850 1.1 830 0.2 820 4 SCO2 0.9 1280 1.7 1290 1.5 1280 0.4 1250 5 SCSL1 0.6 760 1.4 780 1.2 750 0.3 750 6 SCSL2 0.7 1190 1.5 1210 1.3 1160 0.3 1180 7 SCH1 0.7 860 1.4 920 1.1 900 0.4 850 8 SCH2 0.8 1230 1.6 1240 1.4 1220 0.2 1220 Fig. 2 The CO2 emission for the four Saccharomyces cerevisiae yeast strings Examining Table 1, Fig. 2 and 3 we notice that the fermentation process produced by the irradiated samples (batch having the suffix 2) is more intense, which is proved by the increased CO2 emission and by the increased maltasic activity. 4. Conclusions and discussions One of the efficient procedures to select high productivity yeasts is irradiating the samples with nuclear radiation. To our knowledge, results of ÃŽ ² irradiation on yeast have not been reported yet and the literature is poor in ÃŽ ² yeast irradiation [11]. Examining the results we can conclude that for all four Saccharomyces cerevisiae yeast strings the low 12 Gray ÃŽ ² irradiation dosis had a stimulating effect in respect of the fermentation process. The SCO and SCH strings had the higher stimulation effect. Fig. 3 The maltasic activity for the four Saccharomyces cerevisiae yeast strings We believe that the differences are produced by the yeast genome changes produced by à ¯Ã‚ Ã‚ ¢ irradiation. The results of this ongoing study revealed that the small irradiation doses used in the work reported here produce measurable improvement in the fermentation parameters. Special care must be taken in evaluating the side effects of the à ¯Ã‚ Ã‚ ¢ irradiation REFERENCES V.I. Kryukov, V.I. Shishkin, S.F. Sokolenko, Radiacionnaja biologija. Radioekologija, 36, 209, (1996). I.W. Mericle, R.P. Mericle, Radiat. Botany, 7, 449, (1967). D. Chicea, M. Racuciu, Romanian Journal of Physics 52, 5-6, 589, (2007). V.A. Sidorov, Naukova dumka, Kiev, (1990). Conter, D. Dupouy, H. Planel, Int J Radiat Blot, 43, 421, (1983). F. Croute, J.P. Soleilhavoup, S. Vidal, S. Dupouy, H. Planel, Rad.Res., 92, 560, (1982). LBNL Isotopes Project Nuclear Data Dissemination Home Page. Retrieved March 11, 2002, from http://ie.lbl.gov/toi.html Ewing, Davis and Reavis, Public Health Lab. 15, 153, (1957). MacFaddin, Media for isolation-cultivation-identification-maintenance of medical bacteria, vol. 1, Williams Wilkins, Baltimore, (1985). H. Kuriyama, W. Mahakarnchanakul, S. Matsui, H. Kobayashi, Biotechnol. Lett., 15 (2), 189, (1993). J. Kiefer, M. Ebert, Biophysik., 6, 3, 271, (1970).

Heat of Formation of Magnesium Oxide

ObjetiveTo determine the heat formation of MgO (Magnesium Oxide) using Hess’s Law, which states the heat within a chemical reaction is independent of the pathway between the initial and final states.IntroductionChemical reactions require heat energy to complete, called an endothermic reaction, or produce heat energy, and thus called an exothermic reaction. The heat energy produced by such reactions can be measured using a calorimeter, a piece of equipment that can isolate the reaction in an insulated container. Using the calorimeter one can then determine the rise and fall in temperature of the reaction. When this temperature change is multiplied by the heat capacity, the amount of heat needed to raise the temperature of a body by one degree, we can measure the change in converting our initial components (reactants) to their respective products.In this experiment we will measure the amount of heat released from 3 reactions (ΔHA ΔHB ΔHC) and calculate the sum of all 3 reactions to determine ΔHT, which will give us the heat formation of MgO. If Hess’s law holds true and barring minimal experimental error, the pathway we use to determine ΔHT should have no bearing on our calculation matching the accepted calculation of MgO.MethodsAs per lab manual we used a calibrated calorimeter (using a rounded end thermometer so as to not puncture a hole in the calorimeter) to determine the heats of reaction for Magnesium (Mg) with Hydrochloric Acid (HCl) and Hydrochloric Acid with Magnesium Oxide (MgO). Then using mathematical formulas we were able to calculate the heat formation of MgO, which is measured in kJ/Mol. Since both reactions are in dilute water solutions of  HCl it was necessary to know the heat capacity of water, but because some heat would be transferred to the calorimeter whose heat capacity was unknown, we had to record a correction factor (x) based upon the specific heat of water using the equation [m(h2o)+X]Cwater+Δwate r=-1(m(ice water)CwaterΔtice water).We then recorded the mass (m) of room temperature water and ice water each in a respective cup and then poured the ice water into the room temperature water and recorded the temperature change. By knowing (x) we could then calculate the heat of reaction for Mg with HCl (ΔHA kJ/mol) and for HCl with MgO (ΔHB kJ/mol) using the equation q=m(HCl+X)C ΔT where m is the mass of the reactant used with Mg + X, C is the heat capacity of water (4.184 J/g °C), and ΔT is the total temperature change in each reaction. Using the results of these calculations and Hess’s law we can then determine the heat formation for MgO.DataAll mass readings are given in units of grams (g), and all temperature readings are given in degrees Celsius ( °C).Part AMass of the Calorimeter + RoomTemp Water (g)48.08Mass of room temp water (g)46.29Mass of Cal + room temp water + icewater (g)115.40Mass of ice water (g)67.32Temp of room temp water ( °C)42. 4Temp of the ice water ( °C)0.1Final temp. of room temp water ( °C)17.3Change in temp of ice water ( °C)17.2Change of temp of room temp water ( °C)-25.1Mass of the calorimeter (g)1.79Part 2AMass of Calorimeter (g)1.79Mass of Cal + HCl (g)103.55Mass of HCL (g)101.76Mass of Mg (g)0.5Temperature of HCl ( °C)20.3Final temperature of HCl + Mg ( °C)42.0Change in Temperature ( °C)21.7Part BMass of Calorimeter (g)1.79Mass of Cal + HCl (g)101.76Mass of HCl (g)99.88Mass of MgO (g)0.8Temperature of HCl ( °C)20.3Final temperature of HCl + MgO ( °C)25.8Change in Temperature ( °C)5.50Results and DiscussionTo calculate X using the equation [m(h2o)+X]Cwater+Δwater=-1(m(ice water)CwaterΔtice water) the variable X must be isolated and doing so we were than able to calculate the correction factor:Based on the calculations of the calorimeter correction factor, X was determined to be 0.158 g. Then using the equation q=m(HCl+X)C *ΔT, where q is equal to the amount of energ y given off, and than calculating the value in -kJ/Mol (because these are exothermic reactions) we were able to determine ΔHA and ΔHB.qA=m(HCl+X)C xΔTqA=(101.76 g + 0.158 g) x 4.184 J/g °C x 21.7 °CqA= 9250 J = 9.250 kJ 9.253602176qB= m(HCl+X)C xΔTqB=(101.76 g + 0.158 g) x 4.184 J/g °C x 5.50 °CqB=2350 J = 2.350 kJTo then calculate the heat formation of MgO ΔHT, the sum of all the reactions must be determined including ΔHC, the heat formation of water, which is already predetermined to be -285.8 kJ/mol. However to determine the proper equation for ΔHT, the stoichiometric equations must first be balanced:Therefore the heat formation of MgO was determined to be -618.35 kJ/mol. According to the textbook, the accepted value for ΔHT=-601.8 kJ/mol. To determine the accuracy of the calculation we can determine the % error:As far as accuracy goes a percent error of 2.75% is very acceptable. Because the methods of the experiment were conducted using a crude calorimeter I would have expected the percent error to be higher, assuming that because of it’s construction it would not have very high efficiency.I would expect that any error that might have occurred happened during the transference from one cup to another. Because the substances were transferred so quickly and taking into account the number of seconds that it took to replace the thermometer to begin recording data again it is possible that energy was either lost in the transfer or energy was lost before the recording was actually able to begin.ConclusionIn this lab we were able to determine the heat of formation of MgO using a simply constructed calorimeter, which was found to be -618.35 kJ/mol.