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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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自然科學 大學

請問第七題怎麼解

60 s, turn 90 20 km/h for 2.0 min, turn 90° to the point, (a) how far are you from your starting point, and what direction relative to your initial direction of travel are you? V During volcanic eruptions, chunks of solid rock can be blasted out of the volcano; these projectiles are called volcanic bombs. Figure 4-22 shows a cross section of Mt. Fuji, in Japan. (a) At what initial speed would a bomb have to be ejected, at angle 0o = 60.0° to the horizontal, from the vent at A in order to fall at the foot of the volcano at B, at vertical distance h = 2.60 km and horizontal distance d = 9.40 km? Ignore, for the moment, the effects of air on the bomb's travel. (b) What would be the time of flight? (c) Would the effect of the air increase or decrease your answer in (a)?onatlar slow orl w moito Movisio Olovo vibolov te tootsodio dos olvistatani se moltotib nur no vodo as vd botu 29 vd baidot otsi Nomstl moll bottom 12 A plane flies 5 then 1100 km sout) trip, what are the displacement, the velocity, and (e) is 13 An astronau of 4.5 m. (a) Wha eration has a ma minute are requ period of the m 14 A basebal mum height al after reaching that is 86.0 m (a) What may ball? (b) How the ball strike blitt 00 Troede Vibolov sister sam 12 d B 15 The ran also on the place to plac broad jump (where g= by how mu instead in 1 Figure 4-22 Problem 7. 8 Oasis A is 90 km due west of oasis B. A desert camel leaves A and takes 55 h to walk 75 km at 37° north of due east. Next it takes 45 h to walk 65 km due south. Then it rests for 5.0 h. What are the (G) magnitu Cia

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