Conversion factors examples

You can convert between moles and number of representative particles by multiplying the known quantity by the proper conversion factor. Example Problem 10.1 further illustrates the conversion process. 

Exact numbers, such as the stoichiometric coefficients in a chemical formula or reaction, and unit conversion factors, have an infinite number of significant figures. A mole of CaCb, for example, contains exactly two moles of chloride and one mole of calcium. In the equality... 

The conversion factors are presented for ready adaptation to computer readout and electronic data transmission. The factors are written as a number equal to or greater than one and less than 10, with six or fewer decimal places. The number is followed by E (for exponent), a plus or minus symbol, and two digits which indicate the power of 10 by which the number must be multiphed to obtain the correct value. Eor example ... 

The water-vapor transmission rate (WVTR) is another descriptor of barrier polymers. Strictly, it is not a permeabihty coefficient. The dimensions are quantity times thickness in the numerator and area times a time interval in the denominator. These dimensions do not have a pressure dimension in the denominator as does the permeabihty. Common commercial units for WVTR are (gmil)/(100 in. d). Table 2 contains conversion factors for several common units for WVTR. This text uses the preferred nmol/(m-s). The WVTR describes the rate that water molecules move through a film when one side has a humid environment and the other side is dry. The WVTR is a strong function of temperature because both the water content of the air and the permeabihty are direcdy related to temperature. Eor the WVTR to be useful, the water-vapor pressure difference for the value must be reported. Both these facts are recognized by specifying the relative humidity and temperature for the WVTR value. This enables the user to calculate the water-vapor pressure difference. Eor example, the common conditions are 90% relative humidity (rh) at 37.8°C, which means the pressure difference is 5.89 kPa (44 mm Hg). 

U.S. regulations define this standard as foUows proof spirit shaU be held to be that alcohoHc Hquor which contains one-half its volume of alcohol of a specific gravity of 0.7939 at 15.6°C ie, the figure for proof is always twice the percent alcohol content by volume. For example, 100° proof means 50% alcohol by volume. In the United Kingdom as weU as Canada, proof spirit is such that at 10.6°C alcohol weighs exactiy twelve-thirteenths of the weight of an equal bulk of distiUed water. A proof of 87.7° indicates an alcohol concentration of 50%. A conversion factor of 1.142 can be used to change British proof to U.S. proof. 

Table 1-7 provides a number of useful conversion factors. To make a conversion of an element in U.S. customary units to SI units, one multiplies the value of the U.S. customary unit, found on the left side in the table, by the equivalent value on the right side. For example, to convert 10 British thermal units to joules, one multiplies 10 by 1054.4 to obtain 10544 joules. 

Conversion factors can be easily remembered if altered slightly, but not significantly enough to affect shortcut calculations. Here are some examples ... 

Converting a measurement from one unit to anotlier can conveniently be accomplished by using unit conversion factors, tliese factors are obtained from tlie simple equation that relates tlie two units numerically. The following is an example of a unit conversion factor... 

It is often necessary to convert a measurement expressed in one unit (e.g., cubic centimeters) to another unit (liters). To do this we follow what is known as a conversion factor approach. For example, to convert a volume of 536 cm3 to liters, the relation... 

This conversion factor is exact the inch is defined to be exactly 2.54 cm. The other factors listed in this column are approximate, quoted to four significant figures. Additional digits are available if needed for vary accurate calculations. For example, the pound is defined to be 453.59237 g. 

Here, as in so many other cases, a conversion factor approach is used (Example 4.1). 

This rule allows you to find AH corresponding to any desired amount of reactant or product. To do this, you follow the conversion-factor approach used in Chapter 3 with ordinary chemical equations. Consider, for example,... 

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... 

Pressure units are summarized in Table 4.1. It is important to be familiar with them and to be able to make conversions between them. In Example 4.2, for instance, the pressure in pascals could have been obtained by using a conversion factor derived from Table 4.1 ... 

Integers and exact numbers In multiplication or division by an integer or an exact number, the uncertainty of the result is determined by the measured value. Some unit conversion factors are defined exactly, even though they are not whole numbers. For example, 1 in. is defined as exactly 2.54 cm and the 273.15 in the conversion between Celsius and Kelvin temperatures is exact so 100.000°C converts into 373.150 K. 

For example, glutamic-oxalacetic transaminase activity can be standardized with oxalacetate but not with "convenient" substances such as pyruvate (J ). When reference serums are used, the label value should be confirmed at frequent intervals by the actual method being used routinely, as label values can be in error (19). Conversion factors to convert the results obtained by one method into those obtained by another can give erroneous results and should not be used. 

For a comparison of experimental Mossbauer isomer shifts, the values have to be referenced to a common standard. According to (4.23), the results of a measurement depend on the type of source material, for example, Co diffused into rhodium, palladium, platinum, or other metals. For Fe Mossbauer spectroscopy, the spectrometer is usually calibrated by using the known absorption spectrum of metallic iron (a-phase). Therefore, Fe isomer shifts are commonly reported relative to the centroid of the magnetically split spectrum of a-iron (Sect. 3.1.3). Conversion factors for sodium nitroprusside dihydrate, Na2[Fe(CN)5N0]-2H20, or sodium ferrocyanide, Na4[Fe(CN)]6, which have also been used as reference materials, are found in Table 3.1. Reference materials for other isotopes are given in Table 1.3 of [18] in Chap. 1. 

The use of non-SI units is strongly discouraged. For these units there often do not exist standards, and for historical reasons the same denomination may mean sundry units. For example, it is common practice in theoretical chemistry to state energy values in kilocalories. However, to convert a calorie to the SI unit Joule, there exist different conversion factors ... 

Where, for convenience, other than SI units have been used on figures or diagrams, the scales are also given in SI units, or the appropriate conversion factors are given in the text. The answers to some examples are given in British engineering units as well as SI, to help illustrate the significance of the values. 

The conclusion that dimensionless numerical values are universal is valid only if a consistent system of units is used for all quantities in a given equation. If such is not the case, then the numerical quantities may include conversion factors relating the different units. For example, the velocity (F) of a fluid flowing in a pipe can be related to the volumetric flow rate (Q) and the internal pipe diameter (D) by any of the following equations ... 

MeV. WL-R = 100% x WL/radon concentrations (pCi/1). The dose conversion factor of 0.7 rad/working level month (WLM) (Harley and Pasternack, 1982) was used to calculate the mean absorbed dose to the epithelial cells and a quality factor (OF) of 20 was applied to convert the absorbed dose to dose equivalent rate. For example, from the average value of (WL) obtained from the arithmetic mean radon concentrations measured in the living area during winter and summer in South Carolina (Table I), the calculated dose equivalent rate is 4.1 rem/yr, e.g.,... 

Particle size is a major factor which determines the alpha dose conversion factor for radon daughters (mGy/WLM). Data on indoor environments are emerging and indicate that a variety of specific conditions exist. For example, a dose factor four times that for a nominal occupational or environmental exposure exists if kerosene heater particles dominate the indoor aerosol and four times smaller if a hygroscopic particle dominates. 

Refer to Section 1-9, the conversion factors listed in Table 1-8, and Example 1-9. 

Refer to Appendix A, Table 1-8 for conversion factors, and Example 1-4. 

A The molar mass of halothane is given in Example 3-3 in the text as 197.4 g/mol. The rest of the solution uses conversion factors to change units. 

In the example, 0.207 g H2 is collected from 1.97 g alloy the alloy is 6.3% Cu by mass. This information provides the conversion factors we need. 

B Unfortunately, we cannot use the result of Example 26-5 ( 0.0045 u = 4.2 MeV ) because it is expressed to only two significant figures, and we begin with four significant figures. But, we essentially work backwards through that calculation. The last conversion factor is from Table 2-1. 

We use the conversion factor between number of curies and mass of 1311 which was developed in the Summarizing Example. 

Table 1.3 gives some commonly used non-SI units for certain quantities, together with conversion factors relating them to SI units. We use these in some examples and problems, except for the calorie unit of energy. This last, however, is frequently encountered. 

The best quality to be found may be a temperature, a temperature program or profile, a concentration, a conversion, a yield of preferred product, kind of reactor, size of reactor, daily production, profit or cost — a maximum or minimum of some of these factors. Examples of some of these cases are in this group of problems. When mathematical equations can be formulated, peaks or valleys are found by elementary mathematics or graphically. With several independent variables quite sophisticated mathematical procedures are available to find optima. Here a case of two variables occurs in problem P4.12.ll that is solved graphically. The application of Lagrange Multipliers for finding constrained optima is made in problem P4.ll.19. 

To use the proportion method to convert units, set up a proportion as described in Chapter 5. Keep the units consistent on both sides of the proportion. For example, if you want to convert 50.8 centimeters to inches, set up a proportion, such as meter = centimeter and substitute in tie given values on one side, tie conversion factor on tie other yyq = -yyy. Cross-multiply to get 2.54 xs=lx 50.8. Now, divide 50.8 by 2.54 to get n = 20 inches. 

Example 10-1 Fuel Flow Rate for 1 Ampere of Current (Conversion Factor Derivation)... 

Examples. Let us now work out some examples. The energies are given in kcal/mol using the conversion factor 1 hartree = 627.51 kcal/mol. Distances... 

A key aspect of metal oxides is that they possess multiple functional properties acid-base, electron transfer and transport, chemisorption by a and 7i-bonding of hydrocarbons, O-insertion and H-abstraction, etc. This multi-functionality allows them to catalyze complex selective multistep transformations of hydrocarbons, as well as other catalytic reactions (NO,c conversion, for example). The control of the catalyst multi-functionality requires the ability to control not only the nanostructure, e.g. the nano-scale environment around the active site, " but also the nano-architecture, e.g. the 3D spatial organization of nano-entities. The active site is not the only relevant aspect for catalysis. The local area around the active site orients or assists the coordination of the reactants, and may induce sterical constrains on the transition state, and influences short-range transport (nano-scale level). Therefore, it plays a critical role in determining the reactivity and selectivity in multiple pathways of transformation. In addition, there are indications pointing out that the dynamics of adsorbed species, e.g. their mobility during the catalytic processes which is also an important factor determining the catalytic performances in complex surface reaction, " is influenced by the nanoarchitecture. 

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