Graduated cylinder, measuring volume with

Tap density (ptap) is an extension of bulk density measurements, and the procedure used to measure the tap density again varies from lab to lab and can affect the final results. To measure tap density, a graduated cylinder is filled with powder and the weight and volume are recorded. The difference observed between procedures is the number of taps used for the measurement. In some cases, a particular number of taps is used, such as 200 [65], 500 [66], or even 1000 taps [67]. Other procedures involve tapping the cylinder for a number of times, recording the volume, and repeating the procedure until the volume remains constant [68]. This method ensures more consistent results. 

Modem Erlenmeyer flasks and beakers have approximate volume calibrations fused into the glass, but these are very approximate. Somewhat more accurate volumetric measurements are made in the 10-mL graduated cylinders. For volumes less than about 4 mL, use a graduated pipette. Never apply suction to a pipette by mouth. The pipette can be fitted with a small rubber bulb. A Pasteur pipette can be converted into a calibrated pipette with the addition of a plastic syringe body [see Fig. 11(d)] or you can calibrate it at 0.5, 1.0, and 1.5 ml and put three file scratches on the tube this eliminates the need to use a syringe with this Pasteur pipette in the future. Also see the Pasteur pipette calibration marks in the back of this book. You should find among your equipment a 1-mL pipette, calibrated in hundredths of a milliliter [Fig. 11(a)]. Determine whether it is designed to... 

Take a graduated cylinder, fill it with some measurable amount of water, and record this volume. Next, carefully place the nail into the graduate, and the water level will rise. In order to be accurate, the nail must be completely submerged. Now, record the new volume. The volume of the nail will be the difference between the two water levels. Look at the formula here ... 

Even though the two volume measurements appear to be equal, they really convey different information. The quantity 25 mL means that the volume is between 24 mL and 26 mL, whereas the quantity 25.00 mL means that the volume is between 24.99 mL and 25.01 mL. The pipet measures volume with much greater precision than does the graduated cylinder. 

If you used a buret to collect H2 in FIGURE 12.1, determine the uncalibrated volume between the 50-mL mark and the stopcock or pinchcock of the buret by filling that volume with water, draining it into a 10-mL graduated cylinder, measuring the volume, and recording it in TABLE 12.1. Remember that this must be added to your volume of H2 collected to get total volume of H2 collected in TABLE 12.2. 

Step 4. Finally, the apparatus can be emptied (for instance, by pushing with nitrogen gas) and the liquids collected in another graduated cylinder the volume of the stationary phase is V3. For simplification purposes, the extracolumn volumes are neglected. Three measurements of the stationary phase retention are available ... 

Analytical chemists use a variety of glassware to measure volume, several examples of which are shown in Figure 2.4. The type of glassware used depends on how exact the volume needs to be. Beakers, dropping pipets, and graduated cylinders are used to measure volumes approximately, typically with errors of several percent. 

Calculate the molar concentration of NaCl, to the correct number of significant figures, if 1.917 g of NaCl is placed in a beaker and dissolved in 50 mF of water measured with a graduated cylinder. This solution is quantitatively transferred to a 250-mF volumetric flask and diluted to volume. Calculate the concentration of this second solution to the correct number of significant figures. 

A standard solution of Mn + was prepared by dissolving 0.250 g of Mn in 10 ml of concentrated HNO3 (measured with a graduated cylinder). The resulting solution was quantitatively transferred to a 100-mL volumetric flask and diluted to volume with distilled water. A 10-mL aliquot of the solution was pipeted into a 500-mL volumetric flask and diluted to volume, (a) Express the concentration of Mn in parts per million, and estimate uncertainty by a propagation of uncertainty calculation, (b) Would the uncertainty in the solution s concentration be improved... 

Figure 18. Procedure for EPV (effective pore volume) measurement (a) a 50 g MnO, sample is placed in a 100 mL graduated cylinder (2) water is added gradually in 0.5 mL portions (3) with a stopper in place, the cylinder is turned upside down 10 times while being shaken (4) the cylinder is droppes 4 cm onto a wooden surface (5) the Mn02 sample volume is read after 5 and 10 taps (i.e., drops).

To find the starting volume of air in the bottle, fill the bottle with water. Use the graduated cylinder to accurately measure the volume of the water in the bottle. 

Whether the volume measurements are for preparing solutions to be used in such a procedure, for transferring an appropriate volume of solution or solvent for such an analysis, etc., they need not be accurate since the outcome will be either only qualitative or not necessarily accurate. Such volumes should, however, be measured with other marked glassware, such as graduated cylinders or marked beakers and flasks. 

Prepare 1 L of 0.10 MHC1 by diluting the appropriate volume of concentrated HCl (12.0 M). Use a 1-L glass bottle and fill half of it with water before adding the concentrated acid. Use a graduated cylinder to measure the acid. Add more water to have about 1 L, shake well, and label. 

The density of an irregularly shaped solid is usually determined by measuring the mass and then measuring the volume of liquid that it displaces. The volume of liquid in a graduated cylinder is measured before the object is submerged and then measured again with the object submerged. The difference in the volume equals the volume of the object. 

To determine the density of a liquid, the mass in grams of a measured volume of liquid in milliliters is determined. The density is calculated from these measurements. The volume may be measured by a variety of devices, such as a graduated cylinder, pipet, or buret. Very precise determinations of volume are measured with pycnometers. These devices hold a specified volume. A cap or stopper with a capillary overflow tube ensures repeatability in the measurement. See Figure 15.15. 

Place 500 ml of water in a 1 L volumetric flask. Carefully measure 21 ml of cone, hydrochloric acid in a 25 ml graduated cylinder and add to the flask. Rinse the cylinder with water and add the washings to the flask. Mix, dilute to volume and mix again. Add 0.5 ml of Brij 35 and mix thoroughly. 

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