Empirical Formula Lab Report Essays

Empirical Formula Lab Report Essays Empirical Formula Lab Report Paper Empirical Formula Lab Report Paper The molecular formula represents the number of all elements in a compound. The empirical is the simplest whole number ratio of the elements in that compound. Combustion reactions always involve oxygen and are almost always exothermic. Exothermic reactions give off energy in heat form. The purpose of this experiment is to find the empirical formula of a compound using whole numbers. To investigate this experiment, the masses of the metal and gas were measured to obtain the empirical formula of the compound. PROCEDURE Before starting the experiment, the materials needed were gathered: crucible ND lid, Bunsen burner, denizen or distilled water, striker, magnesium ribbon, sandpaper (if needed), clay triangle, wire pad, crucible tongs, electronic scale, ring clamp, experiment stand, paper to record data. Two of each necessary material was gathered in order to conduct two trials at once. To prepare for the experiment, the ring clamp was attached to the stand at about 2/as the way up the stand. The crucible and lid were rinsed with water, dried, and then placed on a clay triangle. The Bunsen burner was hooked up to the gas line and the gas was turned on. The fire was started with the striker and the flame was adjusted o the height of the ring clamp. The crucible and lid were heated gently for 4-6 minutes until the bottom of the crucible became red. The flame was intensified and the crucible and lid were heated for another 10-12 minutes. The crucible and lid were allowed to cool on the wire pad. The mass of the cooled crucible and lid was recorded using the electronic scale. This procedure was repeated once more for each trial. In each trial, the ribbon was placed into the crucible and the lid was placed over it. The mass of the crucible, lid and magnesium was recorded. The crucible containing the magnesium was heated gently for 2-3 minutes. The heat was gradually intensified and heated for another 2-3 minutes. One side of the lid was lifted with the crucible tongs to allow the oxygen inside. The metal started glowing. The crucible, lid and compound were heated for another 3 minutes. The metal was checked periodically until no more glowing was observed. The crucible was then removed from heat and then cooled on the wire pad. 3 drops of denizen water was added to the cooled compound. The crucible was reheated with the lid partially off, allowing the water vapor to escape. The sample was heated slowly and then the heat was intensified for 15-17 minutes. The crucible, lid and compound were allowed to cool on the wire pad. The mass of the crucible, lid and compound was recorded. The sample was reheated for an extra 5 minutes, then the combined mass of the crucible, lid and metal oxide was measured. Some magnesium oxide escaped, when the crucible was not covered. The crucible had to be slightly ajar when heating up the magnesium, so that oxygen could get to the reaction. Without oxygen, a fire cannot exist. The shininess of the metal MGM turned to a dull appearance as it changed to MGM. As the magnesium reacted to the oxygen, it also reacted with the nitrogen in the air to form magnesium nitride, Among. To expel the nitrogen room the crucible, we added water to the mixture and heated it up. This would cause the Among, to react with the water, H2O, to form ammonia, NH, and magnesium hydroxide, MGM(OH)2. The NH was driven off during the heating. One sign of this reaction was the ammonia smell given off. This is because upon heating, the MGM(OH)2 would break into MGM and H2O, which would be driven off by the heat. The second reheating was so that any remnants of the of the crucible had been converted to MGM. This was also to have an accurate final mass of our product MGM. After the lab, the inside of the crucible was black. This s because the magnesium not only reacted with the oxygen and the nitrogen in the air but also with the porcelain of the crucible. The reason for waiting for the crucible to cool before weighing it was because at higher temperatures, the molecules inside are still active, causing the weight to be off. During Trial 2, the magnesium was not properly burned off and caused the calculations to be off. The magnesium looked as if it had stopped glowing, but the inside coil was not completely burned.

Emperors of Chinas Xia Dynasty

Emperors of Chinas Xia Dynasty According to legend, the Xia Dynasty ruled China beginning more than four thousand years ago. Although no firm documentary evidence has yet been found for this period, it is possible that some form of evidence exists, like the  oracle bones  that have proved the existence of the Shang Dynasty (1600 - 1046 BCE). The Xia Kingdom supposedly grew up along the Yellow River, and its first leader was a sort of community organizer named Yu who got all of the people to cooperate in creating dams and canals to control the annual river floods. As a result, their agricultural production and their population increased, and they selected him to become their leader under the name of Emperor Yu the Great. We know about these legends thanks to much later Chinese historical chronicles such as the  Classic of History  or  Book of Documents.  Some scholars believed that this work was compiled from earlier documents by Confucius himself, but that seems unlikely. Xia history is also recorded in the  Bamboo Annals, another ancient book of unknown authorship, as well as in Sima Qians  Records of the Grand Historian  from 92 BCE. There is often more truth than we might guess in ancient myths and legends. That certainly has proved true in the case of the dynasty that came after the Xia, the Shang, which was long thought to be mythical until archaeologists discovered the above-mentioned oracle bones bearing the names of some of the mythical Shang emperors. Archaeology may one day prove the doubters wrong about the Xia Dynasty as well. Indeed, archaeological work in the Henan and Shanxi provinces, along the ancient course of the Yellow River, has turned up evidence of a complex early Bronze Age culture from the correct time period. Most Chinese scholars are quick to identify this complex, called the Erlitou culture, with the Xia Dynasty, although some foreign scholars are more skeptical. The Erlitou digs reveal an urban civilization with bronze foundries, palatial buildings, and straight, paved roads. Finds from the Erlitou sites also include elaborate tombs. Within those tombs are grave goods including the famous  ding tripod  vessels, one of a class of artifacts known as ritual bronzes. Other finds include bronze wine jugs and jeweled masks, as well as ceramic mugs and jade implements. Unfortunately, the one type of artifact not discovered so far is any trace of writing that conclusively states that the Erlitou site is one and the same with the Xia Dynasty. China’s Xia Dynasty Yu the Great, c. 2205 – c. 2197 BCEEmperor Qi, c. 2146 – c. 2117 BCETai Kang, c. 2117 – c. 2088 BCEZhong Kang, c. 2088 – c. 2075 BCEXiang, c. 2075 – c. 2008 BCEShao Kang, c. 2007 – c. 1985 BCEZhu, c. 1985 – c. 1968 BCEHuai, c. 1968 – c. 1924 BCEMang, c. 1924 – c. 1906 BCEXie, c. 1906 – c. 1890 BCEBu Jiang, c. 1890 – c. 1831 BCEJiong, c. 1831 – c. 1810 BCEJin, c. 1810 – c. 1789 BCEKong Jia, c. 1789 – c. 1758 BCEGao, c. 1758 – c. 1747 BCEFa, c. 1747 – c. 1728 BCEJie, c. 1728 – c. 1675 BCE To learn more, go to the list of China’s Dynasties.