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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 高中

想問12題

Coined in 2020, the term "revenge travel" stems from a feeling of wanting to break free from the monotonous life of lockdowns. After being confined in their homes for months due to the fear of the highly contagious disease and subsequent worldwide lockdowns, many people are more before the pandemic, It appears that now, rather than feeling afraid and worried, people are just 11. to travel even 12. lockdowns. With this mindset, the tourism ready to get back at something; the year 2020 industry has greatly bounced back right after the COVID wave starts declining. Many people want to go somewhere so eagerly as they have felt imprisoned for so long. Take India for example. Many people still go traveling out of sheer frustration and the feeling of annoyance from August to October, generally considered the off-season for travel because of unfavorable weather conditions. 13. the freedom of traveling is being celebrated, everything comes at a price. That is, revenge 14. months of lockdown, which breaks the chain of COVID-19 spread., travel has the potential to As tens of thousands of people flock to popular scenic sites, it is crucial for everyone to observe social 15. the chance to be infected will be the last thing people expect. distancing and mask wearing. Although these new norms can be quite disturbing, in the post pandemic era, people have to be prepared to change their behaviors. 11. (A) compelled A 12. (A) lost to $₁5 2 (B) ambitious (C) reluctant (D) desperate (B) occupied with (C) intended for (D) engaged in

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