Density conversion factors

Like any other conversion factor, density can be used in the inverted form to make conversions ... 

Volume is written to 3 significant figures, such as 1.00 cc, to match the 3 significant figures in the mass. As conversion factors, densities can be used to convert a known volume to mass or a known mass to volume. 

The density of a substance is the ratio of its mass to its volume. Density is a fundamental property of materials and differs from one substance to another. Density can be used to relate two separate units, thus working as a conversion factor. Density is a conversion factor between mass and volume. 

In a practical sense, density can be treated as a conversion factor to relate mass and volume. Knowing that mercury has a density of 13.6 g/mL, we can calculate the mass of 2.6 mL of mercury ... 

It is often necessary to convert a unit that is raised to a power (including negative powers). In such cases, the conversion factor is raised to the same power. For example, to convert a density of 11 700 kg-m-3 into grams per centimeter cubed (g-cm 3), we use the two relations... 

For relatively low pressure drops, the effect of compressibility is negligible, and the general flow equation [Eq. (10-29)] applies. Introducing the conversion factors to give the flow rate in standard cubic feet per hour (scfh) and the density of air at standard conditions (1 atm, 520°R), this equation becomes... 

It is seen that the diameters of bronchioles (averaged over generations 11 - 15) vary little with age. The increase in bronchial size is greater, but still less than might be expected if airways are simply scaled for overall body dimensions (illustrated by the dashed curves in Figure 9, which are functions of body weight W). Since bronchiolar diameter does not change much with age it is likely that the thickness of bronchiolar epithelium is also relatively constant. However, in the case of the bronchi, it is reasonable to assume that epithelial thickness is proportional to bronchial diameter. Thus, it is necessary to use age dependent conversion factors between the surface density of alpha-decays and dose to cells. 

A Both the density and the molar mass of Pb serve as conversion factors. 

The substance is lead. To set up this problem, be sure to begin with the correct initial cimounts. The problem tells you there are 5.65 kg for every half liter of substance. This translates into 5.65 kg/0.5 L. After you ve established the initial value, use conversion factors to find the density ... 

The results of the analysis of one SBS sample are summarized in Table III, in which the ultraviolet optical density and the average height in GPC obtained from the area under curve are listed for each fraction in columns 2 and 3, respectively. A conversion factor of 7.2 obtained from polystyrene (PS) calibration was used to convert the optical density to the styrene contribution to the average chromatogram height which is tabulated in column 4. The difference between columns 3 and 4 was taken as the relative weight of butadiene after being multiplied by 1.37, a correction for the difference in refractive indices of styrene and butadiene (column 5). 

Conversion factors for various pressure units and flow units are given in Table VI.1. Table VI.2 lists values of the ratio d,/do (the density of mercury at a temperature t divided by the density of mercury at 0°C) over the temperature range 0-99°C. Capillary depression corrections for mercury in glass tubes are given in Table VI.3. The complete set of corrections for a pressure measurement is made as follows ... 

A 4.028 m solution of ethylene glycol in water contains 4.028 mol of ethylene glycol per kilogram of water. To find the solution s molarity, we need to find the number of moles of solute per volume (liter) of solution. The volume, in turn, can be found from the mass of the solution by using density as a conversion factor. 

The volume of the solution is obtained from its mass by using density as a conversion factor ... 

X 105 = constant value assuming a G value of 0.66, molar extinction coefficient of 2200 at 25°C., density of 1.024, and unit conversion factors. 

Table II. Conversion Factors Leaf Biomass Density ...

Since density always has two units, and conversion factors have two units, guess what Density is a conversion factor between mass and volume. Don t memorize when you need to multiply by density or divide by density to achieve a required conversion. Let the units tell you what to do. 

You are probably well aware that the pressures at great depths under the ocean are extremely large, and the deeper you go, the greater the pressure that is exerted. Let s start small and look at a beaker filled with water. The beaker has a diameter of 10 cm, and the height of the water is 20 cm. How much pressure does the water exert on the bottom of the beaker To answer this question we simply need to recall that P = FI A. The force involved is the weight of the water contained in the beaker. The weight of the water can be calculated from the mass of the water, and the mass of the water can be calculated from the volume, using density as a conversion factor. 

First, let s convert the pressure difference from units of mmFl20 into pascals. Mercury has a density 13.6 times greater than the density of water, so a column of mercury that exerts the same pressure as a column of water is 13.6 times shorter. So, the pressure is 1.47 torr. Now, using the usual conversion factors, we find the pressure difference is 196 Pa. 

To relate percent by weight to percent weight to volume, we again need to employ the density of the solution. For example, what is the percent by weight of a D5W solution The density of D5W is 1.0157 g/mL. Let s see we need to convert 5.0 g per 100 mL into grams per 100 g. That is, we need to convert the denominator from 100 mL into 100 g. Density is the quantitative relationship between mass and volume. So, let s apply the density as a conversion factor to convert the amount of solution from milliliters into grams. You will find this solution is 4.9% (w/w) glucose. 

Solution This is a steady-flow process for which Eq. (2.10h) applies. The initial and final velocities of water in the storage tanks are negligible, and the term bu2/2gc may be omitted. The remaining terms are expressed in units of (Btu)(lbnl) 1 through use of appropriate conversion factors. At 200(°F) the density of water is 60.1 (lbm)(ft)-3, and l(ft)3 is equivalent to 7.48(gal) thus the mass flow rate is... 

It is generally very difficult to measure total gas column densities through a cloud, while it is relatively straightforward to measure die extinction (essentially optical depth) due to dust at some wavelength. The extinction is related to the total dust column density via a dust model, including a particle size distribution. These dust models are typically not unique, hence the additional constraint from the elemental abundances of dust constituents, in particular Si and Fe. Therefore, the conversion factor between the two is an important number, and significant efforts have been directed toward its measurement. 

U and V respectively. Systeme International (SI) units, described in Appendix B, are used extensively but not slavishly. Chemically convenient quantities such as the gram (g), cubic centimeter (cm ), and hter (L = dm =10 cm ) are still used where useful—densities in g cm , concentrations in mol L , molar masses in g. Conversions of such quantities into their SI equivalents is trivially easy. The situation with pressure is not so simple, since the SI pascal is a very awkward unit. Throughout the text, both bar and atmosphere are used. Generally bar = 10 Pa) is used when a precisely measured pressure is involved, and atmosphere = 760 Torr = 1.01325 X 10 Pa) is used to describe casually the ambient air pressure, which is usually closer to 1 atm than to 1 bar. Standard states for all chemical substances are officially defined at a pressure of 1 bar normal boiling points for liquids are still understood to refer to 1-atm values. The conversion factors given inside the front cover will help in coping with non-SI pressures. 

Figure 9-8. C02 resistances, flux densities,and concentrations within and above a corn crop at night. Height in the turbulent air above the plant canopy is not to scale. Air temperature is 20°C, and the atmospheric air pressure is 0.1 MPa (see Table 8-2 for the conversion factor between mmol m-3 and (xmol mol-1).

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