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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

求解 急 怎麼看都不順眼 第29

,我穿起來很漂亮 24 (A) It looks pretty on me. (C) Whe can 1 it on? ) 25. (A) It's expensive. (B) (C) It is too small to wear. 991473 (B) How much is it? (D) Is it my size?這是我的嗎 (B) I'll take this one. (D) I don't like it, either. (1) 26. (A) How much money do you have? (B) Isn't it expensive? (C) Do you have credit cards? (D) How would you like to pay? [31 【27~29】 27 Basketball has been around for more than one hundred years. It 18 C was invented in 1891 by James Naismith, a PE teacher, who tried hard to think of a game for his students to play inside on a rainy or cold winter day. A Naismith wrote some basic rules and used a peach basket for players to throw a ball in. At that time a soccer ball was used to play in the game. Quite different from modern basketball games, the first அ ones in history were slow because there were no holes in the bottom of the peach baskets. When a player threw a ball in a peach basket, the ball stayed there. The game had to stop so that one of the players could climb up to get the ball. Although the first basketball games seem funny, they were an important start of one of the most popular sports in the world. invent 創造 basic 基本的 k C a p y le li a 11 seem 似乎 n (7) 27. What is the best title for the reading? title 標題 (A) James Naismith (B) PE Classes (C) Sports and Their Rules (D) The History of Basketball 28. What CAN'T we learn from the reading? B (A) The first basketball baskets. (B) The number of players on each team. (C) James Naismith's job. (D) Why James Naismith invented basketball. (B) 29. Which of the following usually has a hole in its bottom? (A) A couch. (B) A mat. 長椅 墊 【30~32] (C) A pot. (D) A tub. |tub 浴缸 Dear Sarah, I have two tickets for the game between the Elephants and the Lions next Tuesday. David said that he could go to the game with 21

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英文 高中

請問第24題為什麼用when🥺🥺🙏🙏

Ľ 23 control by using cruel discipline. They may think that 24 in fact they aren't. Other people will try to keep their pet punishment and intimidation are the best ways to solve a problem d people abuse animals because they are careless. For example, someoné might forget to give their cat water for a few days or leave their dog in a car on a hot day with the windows rolled up. Some people 25 they can handle. By doing so, the hurt animals instead of helping them by taking in more pets animals end up living in a place that's cramped, dirty and unhealthy. Nearly all of these people can learn to understand (F) Keep 26% they are being cruel to animals through basic and proper education and become a better keeper. OK The next biggest group of animal abusers does it on purpose, but only for a short period of time. For example, a group of kids may throw rocks at a nest of baby birds they happen to see, or hurt a 22 Beat 28 everyone else is doing. in their neighborhood. These people are usually young, and they aren't thinking. Mostly, they do so out of the peer pressure or the need to impress each other. They just go along with This last group of abusers is the worst. These are people who intentionally hurt animals because it makes them feel powerful. By doing so, they think they control the animals. Others enjoy pain and violence. All of the people in the last group suffer from serious, psychological problems y not go away on their own. They often need the help of licensed professionals-like a psychologist. Without help, their psychological problems can that will probably HC 30 them for their whole lives. to that stray (G) what simply 第4頁 共10頁 (H) haunt when (I) with 29 (E) under (J) than 實際与前述不同

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