For burets

Hand washing typically involves the appropriate soap and a brush. For burets, a cylindrical brush with a long handle (buret brush) is used to scrub the inner wall. With flasks, a bottle or test tube brush is used to clean the neck. Also, there are special bent brushes available to contact and scrub the inside of the base of the flask... 

Titrocolormat is the name we have given to the basic titration instrument which consists of a metal cabinet housing electrical components and supporting optical components, a magnetic stirrer, and a titration vessel. A support rod is provided for burets and refill vessels. Electrical outlets in the rear of the cabinet provide for connection to power, lamp, buret, stirrer, photocell, recorder, and printer. The titration vessels are held on top of a magnetic stirrer which is raised and lowered by a lever control, placing the vessels into or out of the optical beam. 

Gordus, A. A. Statistical Evaluation of Glass Data for Two Buret Readings, /. Chem. Educ. 1987, 64, 516-511. 

The volumes of water in two burets are read, and the difference between the volumes are calculated. Students analyze the data by drawing histograms for each of the three volumes, comparing results with those predicted for a normal distribution. 

Table 9.1), with the choice of buret determined by the demands of the analysis. The accuracy obtainable with a buret can be improved by calibrating it over several intermediate ranges of volumes using the same method described in Chapter 5 for calibrating pipets. In this manner, the volume of titrant delivered can be corrected for any variations in the buret s internal diameter. 

In practice, however, any improvement in the sensitivity of an acid-base titration due to an increase in k is offset by a decrease in the precision of the equivalence point volume when the buret needs to be refilled. Consequently, standard analytical procedures for acid-base titrimetry are usually written to ensure that titrations require 60-100% of the buret s volume. 

The titrant in a conventional titration is replaced in a coulometric titration by a constant-current source whose current is analogous to the titrant s molarity. The time needed for an exhaustive electrolysis takes the place of the volume of titrant, and the switch for starting and stopping the electrolysis serves the same function as a buret s stopcock. 

Good measurement practices (GMPs) describe operations specific to a technique. In general, GMPs provide instructions for maintaining, calibrating, and using the equipment and instrumentation that form the basis for a specific technique. For example, a GMP for a titration describes how to calibrate a buret (if nec-... 

Write directives outlining good measurement practices for (a) a buret, (b) a pH meter, and (c) a spectrophotometer. 

Calibrate the detector tube pump for proper volume measurement at least quarterly. Simply connect the pump directly to the bubble meter with a detector mbe in-line. Use a detector mbe and pump from the same manufacturer. Wet the inside of the 100 cc bubble meter with soap solution. For volume calibration, experiment to get the soap bubble even with the zero ml mark of the buret. For piston-type pumps, pull the pump handle all the way out (full pump stroke) and note where the soap bubble stops for bellows-type pumps, compress the bellows fully for automatic pumps, program the pump to take a full pump stroke. 

Nitrtir, n. (-ous) nitride. Cf. Chloriir. Nitrylsaure,/. nitrylic acid (nitrous acid). Niveau, n. level, -flache, /. level surface, -flasche,/. leveling bottle, leveling vessel (as for a gas buret), -rohr, n., -rohre, /. level tube, leveling tube, -stufe, /. (of electrons) energy level. ... 

Titrier-flasche,/. titration bottle (for feeding a buret), -fliissigkeit, /. titrating solution, standard solution, -gerate, n.pl. titrating apparatus, -methode, /. titration method, volumetric method, -saure, /. titrating acid, standard acid. 

The device most commonly used to measure volume in general chemistry is the graduated cylinder. A pipet or buret (Figure 1.8) is used when greater accuracy is required. A pipet is calibrated to deliver a fixed volume of liquid—for example, 25.00 mL—when filled to the mark and allowed to drain. Variable volumes can be delivered accurately by a buret, perhaps to 0.01 mL. 

The experimental setup for a titration is shown in Figure 4.7. The flask contains vinegar, a water solution of a weak organic add called acetic acid. A solution of sodium hydroxide of known concentration is added from a buret. The net ionic equation for the acid-base reaction that occurs is... 

FIGURE L.2 The apparatus typically used for a titration magnetic stirrer flask containing the analyte clamp buret containing the titrant—in this case, potassium hydroxide. 

In a titration, the volume of one solution is known, and we measure the volume of the other solution required for complete reaction. The solution being analyzed is called the analyte, and a known volume is transferred into a flask, usually with a pipet. Then a solution containing a known concentration of reactant is measured into the flask from a buret until all the analyte has reacted. The solution in the buret is called the titrant, and the difference between the initial and the final volume readings of the buret tells us the volume of titrant that has drained into the flask. The determination of concentration or amount by measuring volume is called volumetric analysis. 

As we saw in Section L, titration involves the addition of a solution, called the titrant, from a buret to a flask containing the sample, called the analyte. For example, if an environmental chemist is monitoring acid mine drainage and needs to know the concentration of acid in the water, a sample of the effluent from the mine would be the analyte and a solution of base of known concentration would be the titrant. At the stoichiometric point, the amount of OH " (or 11,0 ) added as titrant is equal to the amount of H30+ (or OH-) initially present in the analyte. The success of the technique depends on our ability to detect this point. We use the techniques in this chapter to identify the roles of different species in determining the pH and to select the appropriate indicator for a titration. 

Well after the stoichiometric point in the titration of a weak acid with a strong base, the pH depends only on the concentration of excess strong base. For example, suppose we went on to add several liters of strong base from a giant buret. The presence of salt produced by the neutralization reaction would be negligible relative to the concentration of excess base. The pH would be that of the nearly pure titrant (the original base solution). 

The general layout of work benches, including hoods, was described in Chapter 2. Now comes the decision about where there should be drawers, cupboards, or other features. Small, shallow drawers, for instance, are just right for storing hydrometers and similar pieces of equipment and should be close to where these are to be used. Burets also need shallow drawers, but they must be wide. Certain pieces of glassware need fairly deep drawers. Much equipment calls for cupboards of certain sizes. 

C04-0141. A student prepared 1.00 L of a solution of NaOH for use in titrations. The solution was standardized by titrating a sample of potassium hydrogen phthalate whose mass was 0.7996 g. Before titration, the buret reading was 0.15 mL. When the indicator changed color, the buret reading was 43.75 mL. Calculate the molarity of the NaOH solution. 

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