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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

請問20題D是錯在 shared garden 嗎

ABCD III. Reading Comprehension (25%) Hi Emily, How are you? Did you get your exam results yet? I have some good news-we finally moved into our new home! I'm so happy because I don't have to share a room with Nina anymore. It's great to have more privacy and Mom says I can decorate my room the way I like. My plan is to paint the walls yellow and hang up a big photograph of New York City, too (it's still my dream to travel there). I also got a new bed which is much bigger and more comfortable than my last one. Q16. C And guess what else? We have our own garden now. Dad's going to grow vegetables like zucchini and cabbage there. He says I can help him, but I'm not very interested in gardening. One good thing is that we're going to have a barbecue party in July! I hope you can come. You can stay with us for the whole weekend, if you're free. I'll let you know the exact date when my parents decide. Write me soon and tell me your news. Love, Cara 0 privacy 隱私 16. Who, most likely, is Nina? photograph H (A) Emily's mom. (B) Cara's mom. (C) Emily's sister. 17. What do we learn about the writer in the second paragraph? (A) Her parents already decorated the new house. (B) She doesn't want to help with painting the walls.ely) (C) She has wanted to visit New York City for some time. exact 確切的 (D) Cara's sister. (A) Three-bedroom house, close to train station. New kitchen and private garden. No pets, please. Studio apartment with balcony, perfect for a single person. Available from the start of July. CROS) stol 1 20/2651902) DOM 2'omy 60 supinu is ni botning SI in to zkow Inshoqmi ynos 916 2h de brucw zielu insionA prinico riqu D) Her old bed was more comfortable than her new one. C 18. Why does the writer say, "And guess what else?" at the start of the third paragraph? bns 239 ano (A) She felt surprised about something. (B) She is explaining how to do something. art (C) She will give another piece of information.do if (D) She doesn't know the answer to a question. 19. Which sentence is certainly true? iog prijesim 6 p16 2016 ALThe writer will cook some vegetables for her family. (B)The writer's parents don't allow friends to stay over.ad lliw (6) (The writer's mother has never grown tomatoes before. (D) The writer is not sure yet when the barbecue will happen. 20. Which is the advertisement for Cara's new home? am siz dvd bein 的力量 # hework b (B) One-bedroom house with beautiful private garden. Electricity and water bills are not included in the rent. (D) Four-bedroom apartment on second floor. Great for a family. Small balcony and shared garden. 212 Kaun.

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