| 单词 | titration |
| 例句 | My life is now a desperate struggle for survival. . . with occasional titration. The Martian 2011-01-01T00:00:00Z Is Kc > 1, < 1, or ≈ 1 for a titration reaction? Chemistry 2019-02-14T00:00:00Z The authors provided evidence that darobactin and BamA bind to each other directly, using a technique called isothermal titration calorimetry, which measures the heat changes associated with physical interactions between molecules. New antibiotics target the outer membrane of bacteria 2019-12-08T05:00:00Z Having convinced doctors to prescribe Subsys to patients who did not need it, prosecutors said, Insys then turned its attention to increasing the dosage, a process known as titration. Drug company put 'profits over patients' with opioid push: prosecutors 2019-04-04T04:00:00Z In the video, sales reps rap about titration, the process of increasing the strength of a patient’s prescription until it reaches the adequate level. Drug company used rap video to push for higher doses, sales 2019-02-15T05:00:00Z She put patients at risk who received extremely inaccurate lab test results from Theranos, for conditions like atrial fibrillation, which required timely titration of drugs. Elizabeth Holmes, Theranos C.E.O. and Silicon Valley Star, Accused of Fraud 2018-03-14T04:00:00Z At the equivalence point in the titration of a weak base with a strong acid, the resulting solution is slightly acidic due to the presence of the conjugate acid. Chemistry 2019-02-14T00:00:00Z External R&D models move resources towards being more flexible and variable, and enable titration of expenditures up and down in a more fluid real-time manner. External Innovation: Force Multiplier For R&D 2015-06-26T04:00:00Z Must a potential chemist grapple with the tap of a titration flask to appreciate the subtleties of reaction synthesis? Practical nonsense 2014-04-16T17:20:04.822Z "The titration method they propose is novel and looks promising," says Herbert Hill, a chemist at Washington State University, Pullman. Device Sniffs Out Black Powder Explosives 2013-05-03T18:35:00Z Either way, it depends too much on science fiction to be the meaningful titration device for winning congressional assent the memo's authors seem to envision. Immigration reform practice masks great test of Republican principle 2013-01-29T16:41:22Z The first example involves a strong acid titration that requires only stoichiometric calculations to derive the solution pH. Chemistry 2019-02-14T00:00:00Z Three ferrets per group were killed on days 3 and 6 after infection for virus titration. Experimental adaptation of an influenza H5 HA confers respiratory droplet transmission to a reassortant H5 HA/H1N1 virus in ferrets 2012-06-20T17:22:43.540Z Students can thus learn chemical titration by pushing king-size molecules around the virtual space. Learning by Playing 2010-09-16T13:08:00Z The titration is complete when the blue colour is so faint that it is almost imperceptible after the flask has been vigorously shaken. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 7 "Arundel, Thomas" to "Athens" To calculate the percentage of effective alkali from the above titrations, it must be first pointed out that in the case of caustic potash or soda aliquot portions are taken. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. Note that the pH at the equivalence point of this titration is significantly greater than 7, as expected when titrating a weak acid with a strong base. Chemistry 2019-02-14T00:00:00Z Three ferrets per group were killed on days 3 and 6 after infection for virus titration. Experimental adaptation of an influenza H5 HA confers respiratory droplet transmission to a reassortant H5 HA/H1N1 virus in ferrets 2012-06-20T17:22:43.540Z In determining the acidity of cream, a definite volume is taken, and the acidity determined by titration, expressing the results as such a per cent of lactic acid. Outlines of dairy bacteriology A concise manual for the use of students in dairying The solution is then ready for titration with the standard permanganate solution. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 7 "Arundel, Thomas" to "Athens" From this titration the amount of acid to be added is again calculated and more acid is added if necessary. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. This volume represents a stoichiometric excess of titrant, and a reaction solution containing both the titration product, acetate ion, and the excess strong titrant. Chemistry 2019-02-14T00:00:00Z Note the amount of n/10 NaOH solution required to complete the titration, and add it to the equivalent of the n/1 NaOH solution previously run in. The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged. The proportion dissolved in the water used for washing was estimated by titration with alkali; the quantity of KOH required was insignificant, equaling O.71 per cent, of the fat originally used. Scientific American Supplement, No. 488, May 9, 1885 The solution is filtered to get rid of the precipitate, and the titration is finished in the nearly clear nitrate, which should be always about 200 cc. in volume. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 7 "Arundel, Thomas" to "Athens" This may be done by titration in alcohol which has been neutralized. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. A summary of pH/volume data pairs for the strong and weak acid titrations is provided in Table 14.2 and plotted as titration curves in Figure 14.18. Chemistry 2019-02-14T00:00:00Z Standardising Nutrient Bouillon.—For example, 1000 c.c. bouillon are prepared; at the first titration it is found 1. The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged. Total alkali.—This constant is determined by titration in the usual way. Researches on Cellulose 1895-1900 As the titration proceeds, the precipitate is filtered off, and the addition of ammoniacal silver solution to the filtrate continued until a drop produces only a slight opacity. The Handbook of Soap Manufacture As only the free fatty acids are readily soluble in the alcohol and the fat itself only slightly mixes with it, the flask should be well agitated toward the end of the titration. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. In the strong acid titration, use of any of the three indicators should yield reasonably sharp color changes and accurate end point determinations. Chemistry 2019-02-14T00:00:00Z The estimation is carried out by means of titration experiments against standard solutions of caustic soda, in the following manner: Method of Estimating the Reaction.— The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged. The acid numbers, determined by titration in the usual way, are 10-20 p.ct. in excess of the theoretical, the difference increasing with the time of boiling. Researches on Cellulose 1895-1900 The ferrous ammonium sulphate solution is previously standardised by titration with a potassium bichromate solution of one-tenth the above strength, made by diluting 10 c.c. of the strong solution to 100 c.c. with water. The Handbook of Soap Manufacture If the analyst suspects that he is dealing with an impure potassium bichromate, the purity can be ascertained by titration against re-sublimed iodine. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. The equivalence point of a titration may be detected visually if a distinct change in the appearance of the sample solution accompanies the completion of the reaction. Chemistry 2019-02-14T00:00:00Z The titration is continued until there is a permanent yellowish turbidity. A Text-book of Assaying: For the Use of Those Connected with Mines. A drop of phenolphthalein is now added, a little water, and the acidity determined by titration with deci-normal baryta solution, and the baryta solution taken calculated as oleic acid. Nitro-Explosives: A Practical Treatise The second titration gives the amount of caustic alkali present, and the difference between the two the proportion of carbonate. The Handbook of Soap Manufacture N/10 Potassium Bichromate—Dissolve 4.903 g. of C. P. potassium bichromate in water and make the volume up to one liter at the temperature at which titrations are to be made. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. Equivalence points may also be detected by measuring some solution property that changes in a predictable way during the course of the titration. Chemistry 2019-02-14T00:00:00Z In each case the titration must be preceded by an exact preparation of the solution to be assayed in order that the iron may be in the right state of oxidation. A Text-book of Assaying: For the Use of Those Connected with Mines. After titration, the solution is filtered through a small 5-1/2 cm. filter paper, which retains the antimony sulphide. Nitro-Explosives: A Practical Treatise When methyl orange solution is used as indicator, titrations must be carried out cold. The Handbook of Soap Manufacture From the difference of the two titrations the alkali present as carbonate is determined. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. Regardless of the approach taken to detect a titration’s equivalence point, the volume of titrant actually measured is called the end point. Chemistry 2019-02-14T00:00:00Z A white precipitate of sulphur will be formed, this will not interfere with the subsequent titration provided it is precipitated in the cold. A Text-book of Assaying: For the Use of Those Connected with Mines. Similarly, a burette used for the titration of the 50 cc. of solution removed should be calibrated under the same conditions as the measuring flasks or pipettes employed with it. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The molecular weight was determined by saponification with alcoholic potash, and subsequent titration of the excess of potash employed. Scientific American Supplement, No. 447, July 26, 1884 Add a few drops of starch paste and continue titration until the blue color has entirely disappeared. Soap-Making Manual A Practical Handbook on the Raw Materials, Their Manipulation, Analysis and Control in the Modern Soap Plant. Properly designed titration methods typically ensure that the difference between the equivalence and end points is negligible. Chemistry 2019-02-14T00:00:00Z The precipitation and titration of the silver arsenate should be exactly as in the assays. A Text-book of Assaying: For the Use of Those Connected with Mines. The student should also be constantly watchful to insure parallel conditions during both standardization and analyst with respect to the final volume of liquid in which a titration takes place. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Small Gay-Lussac burettes may then be used in the titration of only 0.010 meter internal diameter, and graduated into one-twentieth c. c., which allows of great exactitude in the determination. Scientific American Supplement, No. 401, September 8, 1883 When the content of manganese is large, it is sometimes rather long before the solution is ready for titration. Scientific American Supplement, No. 324, March 18, 1882 Note: For these types of titration calculations, it is convenient to recognize that solution molarity is also equal to the number of millimoles of solute per milliliter of solution: Chemistry 2019-02-14T00:00:00Z The student should next practise the titration with bichromate, which is more especially valuable in the estimation of hydrochloric acid solutions. A Text-book of Assaying: For the Use of Those Connected with Mines. If the titration has occupied more than the three minutes required for draining the sides of the burette, the final reading may be taken immediately and recorded in the notebook. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The titration should be performed in a fairly good uniform light. A Text-book of Assaying: For the Use of Those Connected with Mines. From this we also see how advisable it is to stir the liquid frequently during titration. Scientific American Supplement, No. 324, March 18, 1882 This volume is then used to calculate the concentration of analyte in the sample using the stoichiometry of the titration reaction. Chemistry 2019-02-14T00:00:00Z Zinc should not be used as a reducing agent preliminary to a "bichromate" titration. A Text-book of Assaying: For the Use of Those Connected with Mines. If the variation in results is greater than this, refill the burettes and repeat the titration until satisfactory values are obtained. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes On the other hand, nickel produces its full effect; and the quantity of nickel added can be calculated with accuracy from the extent of its interference with the titration. A Text-book of Assaying: For the Use of Those Connected with Mines. The titration is determined by means of iron, a salt of iron or oxalic acid. Scientific American Supplement, No. 324, March 18, 1882 Perform stoichiometric calculations using typical titration and gravimetric data. Chemistry 2019-02-14T00:00:00Z The solution containing the nickel and cobalt with no great excess of acid, is made alkaline by adding 20 c.c. of soda exactly as in preparing for a titration. A Text-book of Assaying: For the Use of Those Connected with Mines. Use a new page in the notebook for each titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes As regards the titration, the process leaves little to be desired; the quantity of "hypo" required is strictly proportional to the copper present, and ordinary variations in the conditions of working are without effect. A Text-book of Assaying: For the Use of Those Connected with Mines. The latter method is hardly practicable, and I never have time to use it, as the titration and all together yields a value of 99.80 in most cases, if accurately executed. Scientific American Supplement, No. 324, March 18, 1882 Additional details regarding titration analysis are provided in the chapter on acid-base equilibria. Chemistry 2019-02-14T00:00:00Z The arsenic was determined by titration with uranium acetate, and 0.200 gram was found. A Text-book of Assaying: For the Use of Those Connected with Mines. They should be retained and marked "correct" or "incorrect," as indicated by the final outcome of the titrations. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The titration is performed in the usual way, running the standard solution of silver nitrate into a solution containing a known weight or volume of the material containing the cyanide. A Text-book of Assaying: For the Use of Those Connected with Mines. The titration.—The solution, containing not much more than 0.1 gram of nickel, and free from the interfering metals, must be cooled. A Text-book of Assaying: For the Use of Those Connected with Mines. For acid-base titrations, solution pH is a useful property to monitor because it varies predictably with the solution composition and, therefore, may be used to monitor the titration’s progress and detect its end point. Chemistry 2019-02-14T00:00:00Z Antimony or bismuth may be present without interfering with the titration. A Text-book of Assaying: For the Use of Those Connected with Mines. As this is too large a quantity for convenient titration, an aliquot portion of the solution is measured off, representing one fifth of the entire quantity. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Nickel interferes with this assay, doing the work of its equivalent of silver; and the quantity of nickel present can be calculated from the amount of its interference in the titration. A Text-book of Assaying: For the Use of Those Connected with Mines. The titration is more fully described under Cyanide, p. A Text-book of Assaying: For the Use of Those Connected with Mines. The following example exercise demonstrates the computation of pH for a titration solution after additions of several specified titrant volumes. Chemistry 2019-02-14T00:00:00Z A number of titrations can be carried on at the same time provided the quantity of copper present in each is about the same. A Text-book of Assaying: For the Use of Those Connected with Mines. At the close of the titration a large drop of the iron solution should be taken for the test. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The filtrate, cooled and rendered alkaline with soda, is ready for the titration. A Text-book of Assaying: For the Use of Those Connected with Mines. When the residue is clean and sandy-looking, and free from black particles, the flask is cooled, and the residual ferrous iron is determined by titration with "permanganate." A Text-book of Assaying: For the Use of Those Connected with Mines. The second example addresses a weak acid titration requiring equilibrium calculations. Chemistry 2019-02-14T00:00:00Z The following experiments show the conditions necessary for a successful titration. A Text-book of Assaying: For the Use of Those Connected with Mines. The process whereby a !standard solution! is brought into reaction is called !titration!, and the point at which the reaction is exactly completed is called the !end-point!. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Rate of Atmospheric Oxidation.—Solutions ready for titration were exposed to air at the ordinary temperature for varying lengths of time and then titrated. A Text-book of Assaying: For the Use of Those Connected with Mines. Unfortunately this titration serves simply to replace the gravimetric determination, and does not, as many volumetric processes do, lessen the necessity for a complete separation of any other metals which are present. A Text-book of Assaying: For the Use of Those Connected with Mines. Performing additional calculations similar to those in the preceding example permits a more full assessment of titration curves. Chemistry 2019-02-14T00:00:00Z A series of titrations of a copper solution by means of a solution of potassic cyanide gave the following results:— Copper taken. A Text-book of Assaying: For the Use of Those Connected with Mines. The indicators in most common use for acid and alkali titrations are methyl orange, litmus, and phenolphthalein. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The titration of the zinc takes less time, and, with ordinary working, is more trustworthy than the gravimetric method. A Text-book of Assaying: For the Use of Those Connected with Mines. It has the disadvantage of all indirect titrations in that it requires two standard solutions. A Text-book of Assaying: For the Use of Those Connected with Mines. Any of the three indicators will exhibit a reasonably sharp color change at the equivalence point of the strong acid titration, but only phenolphthalein is suitable for use in the weak acid titration. Chemistry 2019-02-14T00:00:00Z Make a series of two or three titrations, using very different quantities of metal in each. A Text-book of Assaying: For the Use of Those Connected with Mines. This explains its usefulness, as referred to later, for the titration of strong acids, such as hydrochloric acid, even in the presence of carbonates or sulphides in solution. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The titration with permanganate of potassium has the advantage of a more distinct finishing point and easier mode of working; its application, however, is somewhat limited by the disturbing effects of hydrochloric acid. A Text-book of Assaying: For the Use of Those Connected with Mines. It is essential to know by experiment that these salts do not exert any effect on the titration. A Text-book of Assaying: For the Use of Those Connected with Mines. The titration curves shown in Figure 14.20 illustrate the choice of a suitable indicator for specific titrations. Chemistry 2019-02-14T00:00:00Z An indirect titration thus requires three determinations, but if more than one assay is to be carried on, two of these need not be repeated. A Text-book of Assaying: For the Use of Those Connected with Mines. This indicator is affected by even so weak an acid as carbonic acid, which must be removed by boiling the solution before titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The student should note that a titration is not completed if a colour is developed on standing for five or ten minutes. A Text-book of Assaying: For the Use of Those Connected with Mines. In the absence of manganese and cobalt the titration may be made without further separation. A Text-book of Assaying: For the Use of Those Connected with Mines. The weak acid titration curve in Figure 14.20 shows that only one of the three indicators is suitable for end point detection. Chemistry 2019-02-14T00:00:00Z Iron, if present, interferes by forming a white flocculent precipitate of ferric arsenate after the addition of the sodium acetate and preliminary to the titration. A Text-book of Assaying: For the Use of Those Connected with Mines. It is the indicator most generally employed for the titration of organic acids. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes In the titration of iron by permanganate solution there are two reactions. A Text-book of Assaying: For the Use of Those Connected with Mines. The titration can then be continued, but more cautiously, and the value in "c.c." for the quantity added be deducted from the final reading. A Text-book of Assaying: For the Use of Those Connected with Mines. Phenolphthalein, on the other hand, exhibits a color change interval that nicely brackets the abrupt change in pH occurring at the titration's equivalence point. Chemistry 2019-02-14T00:00:00Z In the application of this titration to the assay of manganese ores, hydrochloric and hydriodic acids are the only ones likely to be present. A Text-book of Assaying: For the Use of Those Connected with Mines. From the data obtained, calculate the volume of the hydrochloric acid solution which is equivalent to the volume of sodium hydroxide solution used in this titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes If an excess, subtract it from the result of each titration; if a deficit, add it; and use the standard in the usual way. A Text-book of Assaying: For the Use of Those Connected with Mines. In the filtrate the remaining silver, if there should be any, was determined by the ordinary titration, but with "sulphocyanate" of one-tenth the strength. A Text-book of Assaying: For the Use of Those Connected with Mines. These curves are useful in selecting appropriate acid-base indicators that will permit accurate determinations of titration end points. Chemistry 2019-02-14T00:00:00Z This should be remembered, since when titrating arsenic assays with iodine it must be present; and students must avoid confounding the two titrations. A Text-book of Assaying: For the Use of Those Connected with Mines. If no color reappears during this time, complete the titration in the hot solution. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Except when otherwise stated, all titrations should be made at the ordinary temperature; cooling, if necessary, by holding the flask under the tap. A Text-book of Assaying: For the Use of Those Connected with Mines. When a titration is directed to be made in a boiling solution, it must be remembered that the standard solution is cold, and that every addition lowers the temperature of the assay. A Text-book of Assaying: For the Use of Those Connected with Mines. The principles of these indirect titrations become clearer when expressed in a condensed form. A Text-book of Assaying: For the Use of Those Connected with Mines. If the quantity of ferrocyanide required is known within a few c.c., the finishing point is exactly determined in the first titration without any addition of the standard zinc solution. A Text-book of Assaying: For the Use of Those Connected with Mines. The results of titration with a given indicator are, therefore, comparable. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Effect of varying cyanide.—The bulk before titration was in each case 60 c.c.; A Text-book of Assaying: For the Use of Those Connected with Mines. This is for the titration of free iodine, and is practically that which is described under Manganese. A Text-book of Assaying: For the Use of Those Connected with Mines. The delicacy of this reaction is taken advantage of in titrations to determine when free iodine is present. A Text-book of Assaying: For the Use of Those Connected with Mines. If the conditions are held to, the titration is a fairly good one, and differences in the results of an assay will be due to error in the separation. A Text-book of Assaying: For the Use of Those Connected with Mines. The comparison of the acid and alkali solutions was made, using methyl orange as an indicator, while the titration of the oxalic acid is made with the use of phenolphthalein. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The following experiments show the effect of variation in the conditions of titration. A Text-book of Assaying: For the Use of Those Connected with Mines. It is evidently important that the quantity of this salt present in each titration be measured out, so as to avoid variation. A Text-book of Assaying: For the Use of Those Connected with Mines. Effect of Varying Temperature.—The reaction goes on very quickly in the cold, and, since there is no occasion for heating, all titrations should therefore be carried out cold. A Text-book of Assaying: For the Use of Those Connected with Mines. Great care is required with such solutions, both before and during titration. A Text-book of Assaying: For the Use of Those Connected with Mines. It is, in general, true that oxidizable substances are determined by !direct! titration, while oxidizing substances are determined by !indirect! titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Effect of Varying Bicarbonate of Soda.—This salt must be present in each titration in considerable excess, to prevent the interference of free acid. A Text-book of Assaying: For the Use of Those Connected with Mines. Add to each test tube 3 drops of dilute sulphuric acid; that which shows the first appearance of a precipitate marks the point at which the titration is complete. A Text-book of Assaying: For the Use of Those Connected with Mines. Instead of separating and weighing this compound, the phosphoric oxide in it can be determined by titration. A Text-book of Assaying: For the Use of Those Connected with Mines. The ignited precipitate is then dissolved with sulphuric and hydrochloric acids; and the iron determined in the solution by titration with the solution of stannous chloride. A Text-book of Assaying: For the Use of Those Connected with Mines. This procedure is somewhat more time-consuming, but the end-point of the permanganate titration is more permanent. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The following experiments show the effect of variation in the conditions of the titration:— Effect of Varying Temperature.—The solution should be titrated while boiling. A Text-book of Assaying: For the Use of Those Connected with Mines. A similar titration is made with the addition of 100 c.c. of the water to be tested. A Text-book of Assaying: For the Use of Those Connected with Mines. Less permanganate will be required in the second titration, according to the amount of oxygen in the water; and the difference, multiplied by 0.5, will give the weight of the oxygen in milligrams. A Text-book of Assaying: For the Use of Those Connected with Mines. Effect of the Addition of Starch.—The addition of varying quantities of starch has no effect, provided it is added when the titration is nearly finished, as the following experiments show:— Starch added 1.0 c.c. A Text-book of Assaying: For the Use of Those Connected with Mines. As in the case of the bichromate process, it is necessary to reduce the iron completely to the ferrous condition before titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The difference in the two titrations, divided by the last and multiplied by 10, will give the c.c. of permanganate solution used in oxidising the organic matter in the 250 c.c. of water. A Text-book of Assaying: For the Use of Those Connected with Mines. The standardising and titration should be made under the same conditions. A Text-book of Assaying: For the Use of Those Connected with Mines. Effect of Varying Sulphur.—In these and the subsequent experiments the titrations were performed in the presence of 10 grams of sodic acetate and 10 c.c. of acetic acid in the manner already described. A Text-book of Assaying: For the Use of Those Connected with Mines. How much of the ferrous solution will be oxidised in the second titration? A Text-book of Assaying: For the Use of Those Connected with Mines. Stannous chloride may also be used when the titration is made in the presence of hydrochloric acid. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The method of working and the conditions of the titration are the same as for the phosphate titration. A Text-book of Assaying: For the Use of Those Connected with Mines. The solution before titration must contain no free mineral acid, but 5 or 10 c.c. of acetic acid should be present. A Text-book of Assaying: For the Use of Those Connected with Mines. Lime.—Where but little magnesia is present, this is determined by titration with standard acid. A Text-book of Assaying: For the Use of Those Connected with Mines. It should then be checked by another titration with pure sodium carbonate. A Text-book of Assaying: For the Use of Those Connected with Mines. Deduct this volume from the amount of permanganate solution used in the titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The order in which these experiments are given is that in which they were made in an investigation into the conditions under which the titration could most accurately be effected. A Text-book of Assaying: For the Use of Those Connected with Mines. It is well to occasionally replace the water boiled off during titration. A Text-book of Assaying: For the Use of Those Connected with Mines. Effect of Foreign Salts.—In all these experiments 20 c.c. of "sulphuric acid" were used, and the titration was performed in the ordinary way. A Text-book of Assaying: For the Use of Those Connected with Mines. The magnesia having been precipitated as ammonic-magnesic phosphate, which is the usual separation, its weight can be determined volumetrically by the method of titration described under Phosphates. A Text-book of Assaying: For the Use of Those Connected with Mines. It is also desirable that a sufficient excess of the acid should be present to react with a considerable volume of the permanganate solution during the titration, thus increasing the accuracy of the process. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes If a sample of copper contained 0.5 per cent. of arsenic, and 1 gram of it were taken for an assay, how much standard uranium acetate solution would be required in the titration? A Text-book of Assaying: For the Use of Those Connected with Mines. The titration of iodine against sodium thiosulphate, with starch as an indicator, may perhaps be regarded as the most accurate of volumetric processes. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Decant the supernatant liquid through a filter and use the clear filtrate; 5 cc. of this solution are needed for a titration. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes It has been assumed in these rules that the titration has yielded proportional results; but these are not always obtained. A Text-book of Assaying: For the Use of Those Connected with Mines. The liberated iodine is then determined by titration with sodium thiosulphate, as described on page 78. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes Repeat the titration, using a second 25 cc. portion. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes The liquid must be cold at the time of titration and entirely free from nitrous compounds, as these sometimes cause a reddening of the indicator solution. An Introductory Course of Quantitative Chemical Analysis With Explanatory Notes |
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