Volume SI units

A macroscopic sample (which need not be a bar magnet or current-carrying coil), comprised of a very large number of microscopic (atomic) magnetic moments, can be defined as the magnetization, M, as the net magnetic moment per unit volume (SI units A/m, gauss/cm, or emu/cm in the cgs system) ... 

From the discussion it also follows that there Is a certain freedom of choice regarding the units Into which measured quantities are expressed. Recall, however, the restriction that if cross-relationships are to be derived on the basis of Onsager s reciprocal relationships (secs. 1.6.2b and c) the fluxes J. resulting from forces X, must have such dimensions that the product XJ has the dimensions of entropy production per unit time and unit volume (SI units J m K" s ). 

Variables length and volume length SI-unit is the meter, m volume SI-unit is the cubic meter, m (maintained as a multiple of a Kr radiation wavelength)... 

Material Susceptibility X (volume) (SI units) Material Susceptibility X (volume) (SI units)... 

There are a few basic numerical and experimental tools with which you must be familiar. Fundamental measurements in analytical chemistry, such as mass and volume, use base SI units, such as the kilogram (kg) and the liter (L). Other units, such as power, are defined in terms of these base units. When reporting measurements, we must be careful to include only those digits that are significant and to maintain the uncertainty implied by these significant figures when transforming measurements into results. 

In molecular weight determinations it is conventional to dissolve a measured mass of polymer m2 into a volumetric flask and dilute to the mark with an appropriate solvent. We shall use the symbol Cj to designate concentrations in mass per volume units. In practice, 100-ml volumetric flasks are often used, in which case C2 is expressed in grams per 100 ml or grams per deciliter. Even though these are not SI units, they are encountered often enough in the literature to be regarded as conventional solution units in polymer chemistry. 

Dimensionless Quantities. Certain quantities, eg, refractive index and relative density (formerly specific gravity), are expressed by pure numbers. In these cases, the corresponding SI unit is the ratio of the same two SI units, which cancel each other, leaving a dimensionless unit. The SI unit of dimensionless quantities may be expressed as 1. Units for dimensionless quantities such as percent and parts per million (ppm) may also be used with SI in the latter case, it is important to indicate whether the parts per million are by volume or by mass. 

The solubihty coefficient must have units that are consistent with equation 3. In the hterature S has units cc(STP)/(cm atm), where cc(STP) is a molar unit for absorbed permeant (nominally cubic centimeters of gas at standard temperature and pressure) and cm is a volume of polymer. When these units are multiphed by an equihbrium pressure of permeant, concentration units result. In preferred SI units, S has units of nmol /(m GPa). 

Mole The SI unit of quantity the amount of a pure element or chemical compound that contains the same number of atoms or molecules. It is often simpler to use moles rather than volume or mass when working with gases. Moles are given by... 

In this book, we will express our thermodynamic quantities in SI units as much as possible. Thus, length will be expressed in meters (m), mass in kilograms (kg), time in seconds (s), temperature in Kelvins (K), electric current in amperes (A), amount in moles (mol), and luminous intensity in candella (cd). Related units are cubic meters (m3) for volume, Pascals (Pa) for pressure. Joules (J) for energy, and Newtons (N) for force. The gas constant R in SI units has the value of 8.314510 J K l - mol-1, and this is the value we will use almost exclusively in our calculations. 

When making calculations, we will generally convert all data to their values in SI units, since calculations involving SI units give answers in SI units. For example, when calculating the volume of an ideal gas from the equation... 

This law is closely obeyed by real gases under conditions where the actual volume of the molecules is small compared with the total volume, and where the molecules exert only a very small attractive force on one another. These conditions are met at very low pressures when the distance apart of the individual molecules is large. The value of R is then the same for all gases and in SI units has the value of 8314 J/kmol K. 

The constant R is called the gas constant and has the same value for all gases because R is independent of the identity of the gas, we say that it is a universal constant. The value of the gas constant can be found by measuring P, V, n, and T and substituting their values into R = PV/nT. When we use SI units (pressure in pascals, volume in meters cubed, temperature in kelvins, and amount in moles),... 

R is obtained in joules per kelvin per mole R = 8.314 J-K-1-mol" Table 4.2 lists the values of R in a variety of different units which are useful if volume or pressure is reported in other than SI units. For instance, it is sometimes convenient to use R in liter-atmospheres per kelvin per mole R = 8.206 X 10 "2 L-atnvk -mol... 

The international scientific community prefers to work exclusively with a single set of units, the Systeme International (SI), which expresses each fundamental physical quantity in decimally (power of 10) related units. The seven base units of the SI are listed in Table 1-3. The SI unit for volume is obtained from the base unit for length A cube that measures 1 meter on a side has a volume of 1 cubic meter. 

D.3.1.2 Absorbed Dose and Absorbed Dose Rate. The absorbed dose is defined as the energy imparted by the incident radiation to a unit mass of the tissue or organ. The unit of absorbed dose is the rad 1 rad = 100 erg/gram = 0.01 J/kg in any medium. An exposure of 1 R results in a dose to soft tissue of approximately 0.01 J/kg. The SI unit is the gray which is equivalent to 100 rad or 1 J/kg. Internal and external exposures from radiation sources are not usually instantaneous but are distributed over extended periods of time. The resulting rate of change of the absorbed dose to a small volume of mass is referred to as the absorbed dose rate in units of rad/unit time. 

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