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英国论文代写-Theory behind the experiment

2017-08-19 | 来源:51due教员组 | 类别:更多范文

本篇英国论文代写-Theory behind the experiment讲了参考文献应在本节中出现;结束这一假说的明确陈述。一个假设是一个明确的,可测试的语句,包括独立变量和从属变量。介绍应该使用您的数据收集方法将独立/依赖变量的背景研究结合在一起;介绍应该显示你解决问题的路径。本篇代写文章由51due代写平台整理,供大家参考阅读。


Introduction

Introduction that thoroughly yet concisely discusses the theory behind the experiment. References should appear in this section; end with a clear statement of the hypothesis. A hypothesis is an unambiguous, testable statement that includes both independent and dependent variables. The introduction should weave together your background research on the independent/dependent variables with your data collection methods; The introduction should show the path you took to address the problem.

Hard water contains high amount of calcium and magnesium ions. These ions are dissolved from mineral salts of rocks when water flows by. This process occurs naturally, meaning hard water comes from nearly all natural water sources. Although hard water has moderate effect on human health, it poses a lot of serious problems in everyday life, such as breaking boilers, and blocking water pipes. Knowing how many hard ions are contained in hard water is not only useful for quality classification of hard water, but also a crucial step towards hard water treatment.

Double displacement reaction could be used to determine water hardness with some certainty. The main principle are as following. Sodium carbonate will react with calcium ions (mainly in calcium choloride form) to produce sodium chloride and calcium carbonate, which is a precipitant. The chemical equation is stoichiometry. And therefore, the amout of calcium carbonate could be precisely calculated from the amount of sodium carbonate. Since the amount of calcium ions is fixed (hard water sample volume is fixed), the amount of produced calcium carbonate will be determined from the limiting reactant. In other words, the amount of produced calcium carbonate precipant will increase as the amount of sodium carbonate increases, until sodium carbonate is no longer limiting reactant. At that time, the amount of precipant (calcium carbonate) will be theoretically remain unchanged. By using this procedure, the amount of calcium ions of the sample water will be determined. In this experiment, water softener (sodium carbonate) with increasing mass will be added into a group of hard water sample of fixed volume. Limiting reactant and water hardness will be deduced by weighing the mass of precipant.

Conclusions

Conclusions that clearly link data to hypothesis in clear conclusion statements. The conclusion statement should contain 1 sentence hypothesis restatement, 1-2 sentence summary of procedures, 2-4 sentences highlighting significant conclusions (stating specific data), 2-3 sentences for error analysis, 1-2 sentences addressing the next steps (what would be your next research project from here given unlimited funds/time? Think deep here. Simply suggesting another trial is not significant enough. What other questions along this line of thinking could you solve?)

In this experiment, water hardness (calcium ion) was determined by using double displacement reaction. Water softener sodium carbonate was added into a set of hard water samples with fixed volume, i.e., calcium ion content. The reaction between calcium choloride and sodium carbonate is in classic stoichiometry, and produces sodium choloride and calcium carbonate that is a precipant in the solution. Principally, weighing the mass of precipant will bring information on content of calcium ion of the sample water. A set of sodium carbonate with increasing mass will generate a changing amount of precipant. In the experiment, 0.398g, 0.596g, and 0.894g sodium carbonate was added into three trials of hard water sample of 20mL. The softener and water sample was fully mixed by using a magnetic mixer. The precipate was filtered through vacuum filtration device, and was dryed in oven for 20min. The amount of precipant was sequentially measured. A theoretical calculation on the amount of precipant was also obtained. A comparison between experimental data and theoretical calculation shows the mass of precipant remains unchanged after X.XX g sodium carbonate was added. This indicate sodium carbonate is no longer a limiting reactant above X.XXg, and the amount of calcium carbonate was determined as Y.YY g. And the variance of the experimental data are within X.X%. In following experiments, controlling factors that affects measurement accuracy will be investigated, such as drying and filtering process. An optimized protocol will be generated to have improved acurracy. We hope the method will be reliable to determine water hardness of samples from other states in US.


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