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自然科學 大學

為什麼[A(org)]=n[An(org)]成立 (第三張圖equation 7.9) 感謝

Experiment 7 Experiment 7 The partition of Organic acid between Water and Organic solvent Objectives Understand the partition of a solute between two immiscible solvents. Introduction A chemical analysis that is performed primarily with the aid of volumetric glassware (e.g., pipets, burets, volumetric flasks) is called a volumetric analysis. For a volumetric analysis procedure, a known quantity or a carefully measured amount of one substance reacts with a to-be-determined amount of another substance with the reaction occurring in aqueous solution. The volumes of all solutions are carefully measured with volumetric glassware. The known amount of the substance for an analysis is generally measured and available in two ways: 1. As a primary standard: An accurate mass (and thus, moles) of a solid substance is measured on a balance, dissolved in water, and then reacted with the substance being analyzed. 2. As a standard solution: A measured number of moles of substance is present in a measured volume of solution - a solution of known concentration, generally expressed as the molar concentration (or molarity) of the substance. A measured volume of the standard solution then reacts with the substance being analyzed. The reaction of the known substance with the substance to be analyzed, occurring in aqueous solution, is generally conducted by a titration procedure. The titration procedure required a buret to dispense a liquid, called the titrant, into a flask containing the analyte. A reaction is complete when stoichiometric amounts of the reacting substances are combined. In a titration this is the stoichiometric point. In this experiment the stoichiometric point for the acid-base titration is detected using a phenolphthalein indicator. Phenolphthalein is colorless in an acidic solution but pink in a basic solution. The point in the titration at which the phenolphthalein changes color is called the endpoint of the indicator. Indicators are selected so that the stoichiometric point in the titration coincides (at approximately the same pH) with the endpoint of the indicator.

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英文 國中

有人會寫英文短文嗎?

Get Ready to Write things. *識全集中 A Venn diagram can help you compare and contrast two different Ants How they are the same Bees • Live in • Black or brown •Can walk a long way • Birds like to eat them Insects • six legs Live in hives Yellow and black Can •Make e both popular. use a ball exciting How they are different Read the following report comparing ants and bees. Read again and complete the Venn diagram with information that tells you how ants and basketball 219 mod MS 89 and bees are the same or different. Introduction How they are the same How they are different Conclusion Ants and Bees nobuboun There are many kinds of insects in the world. All insects have six legs, but they can be very different. Two insects, which you can see everywhere, are ants and bees. Ants live in nests. Thousands of ants live together. Bees also live together, but they live in hives. Both ants and bees have a queen. The hard working queen lays many eggs. Ants and bees work very hard to find food and build their homes. But be careful because when they get angry, they can hurt you. yart worl hib Ants and bees are also different in many ways. Ants are usually smaller than bees and they are brown or black in color. However, bees are yellow and black. Bees can fly and eat from flowers. This food, which becomes honey, is delicious. On the other hand, ants often walk a long way to find food. Some birds and animals like to eat ants. As you can see, ants and bees are both very interesting no insects. They are the same and different in many ways. Which one do you like? IN LINE

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數學 高中

根本看不懂啦\( ̄▽ ̄;)/

Your report should follow these guidelines, although you may choose how you present it: How to Write a Mathematics Report In writing your report, remember that you are writing up a mathematical story and so, like all good stories, it will need a beginning, a middle and an end. More formally, the main components of this writing style are: Introduction, Formulating the Problem, Solving the problem, Discussion of Results, and Conclusion. We will now consider some of the detail in each of these aspects. Introduction This is the beginning of the story. Give a brief explanation of what the problem is about what the goals of the report are and what will be presented. Assume that your reader does not know what the problem is about or how to solve it. Formulating the problem Translate the situation into a maths problem. Explain how you will begin to solve the problem and break it into simpler stages. Discuss any assumptions made. What quantities are variables and which values are fixed? You may use sub-headings if they assist you. Solving the Problem Show any calculations and mathematical reasoning that you use. (Assume that your reader does not know much maths). Do not show the same types of calculations repetitively. Just give one or two examples of a calculation and then put the rest of the results in a table. Use diagrams or graphs if they assist you. Make general remarks about what you observe in your calculation results and, possibly, why. You may want to criticise your work and go on to improve it in the next section. Explain what you will do next and why. Discussion of Results - Evaluate and Verify Summarise your results if necessary and refer to your mathematical reasoning. Justify procedures used. Interpret your results. First, are they reasonable or does something not look right and need further investigation or checking? Is there a decision to be made? Here is where you should present the decision-making process. Evaluate the strengths and limitations of your solutions. Conclusion Summarise your findings. Refer to the problem outlined in the introduction. Make sure that you answer the question that was asked. Make recommendations. No new material should be presented here.

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