Metric conversion factors

In this unit you will find explanations, examples, and practice dealing with the calculations encountered in the chemistry discussed in this book. The types of calculations included here involve conversion factors, metric use, algebraic manipulations, scientific notation, and significant figures. This unit can be used by itself or be incorporated for assistance with individual units. Unless otherwise noted, all answers are rounded to the hundredth place. The calculator used here is a Casio FX-260. Any calculator that has a log (logarithm) key and an exp (exponent) key is sufficient for these chemical calculations. 

Units. The SI system of units and conversion factors (qv) has been formally adopted worldwide, with the exception of Bmnei, Burma, Yemen, and the United States. The participation of the United States in the metrication movement is evident by the passage of the Metric Acts of 1866 and 1975 and the subsequent estabUshment of the American National Metric Council (private) and the U.S. Metric Board (pubHc) to plan, coordinate, monitor, and encourage the conversion process. 

Table 1-5 Metric Conversion Factors as Exact Numerical...

Customary Unit BallPark Metric Values (Do Not Use As Conversion Factors) ... 

Conversion of units from one system to another is simply carried out if the quantities are expressed in terms of the fundamental units of mass, length, time, temperature. Typical conversion factors for the British and metric systems are ... 

Beginning students often regard the metric system as difficult because it is new to them and because they think they must learn all the English-metric conversion factors (Table 2-3). Engineers do have to work in both systems in the United States, but scientists generally do not work in the English system at all. Once you familiarize yourself with the metric system, it is much easier to work with than the English system is. 

Still other units encountered in the literature and workplace come from various other systems (absolute and otherwise). These include metric systems (c.g.s. and MKS), some of whose units overlap with SI units, and those (FPS) based on English units. The Fahrenheit and Rankine temperature scales correspond to the Celsius and Kelvin, respectively. We do not use these other units, but some conversion factors are given in Appendix A. Regardless of the units specified initially, our approach is to convert the input to SI units where necessary, to do the calculations in SI units, and to convert the output to whatever units are desired. 

Conversion factors for the U.S. Customary System, metric system, and International System ... 

The figures given are taken from the Year Book of the League of Nations for 1938-1939 and have been reduced to metric tons of refined sugar using the official conversion factors, since in some cases tons of raw sugar only were recorded. 

Table 4-2 shows how some of the basic metric units are related to units commonly used in English-speaking countries for nonscientitle measurements. Although the United States, Great Britain, and Canada have officially resolved to convert to the metric system, it will be many years before the conversion is complete. In the meantime, you must learn to convert from one system to the other. The three conversion factors given in Table 4-2 (rounded off to 2.54... 

Dimension measured Metric unit English unit Conversion factor F... 

Metric units, as opposed to the Sysffeme Internationale (SI) units, have been employed thruout this Encycl. For this reason, metric units have been retained in this article. Conversion factors from quantities encountered in Thermochemistry to SI units are listed below Heat Capacity ... 

The international system of units is described in detail in NIST Special Publication 81l,1 and lists of physical constants and conversions factors of selected unit conversions1 5 are given in the following tables. The conversions are presented in matrix format when all of the units are of a convenient order of magnitude. When some of the unit conversions are of tittle value (such as the conversion between metric tons and grains), tabular form is followed, with the less useful units omitted. 

Convert 3.50 yards to (a) millimeters, (b) meters. According to Table 1-2, the conversion factor used to move between the English and metric system (SI) units is 1 in/2.54cm (2.54 x 10-2 m). 

A conversion factor is a statement of equality between two measurements of the same object or property. As a beginning example, let s explore converting between metric quantities. For example, a length of 1 m obviously has a length of 1 m ... 

Notice that our conversion factor between metric quantities has an interesting form. One side gets the prefix multiplier letter (in this case, the c ), and the other side gets the numerical equivalent of the multiplier (in this case, 1 x 10-2). Students sometimes get the number on the wrong side of the conversion factor. If you stick with the definition of the prefix multipliers given in Table 1.2, your conversion factors will always have a prefix multiplier on one side and a number on the other side. Seems fairer that way, doesn t it ... 

You might have learned this form in a previous class. Of course, either form of our conversion factor can be used. However, if you have ever had trouble converting between metric units, you might want to stick with the first version. Learn the prefix multipliers and their numerical meanings. Then, when you write a conversion factor expression, make sure one side gets the letter and the other side gets the number. 

Volume in the metric system is expressed in liters (L) and milliliters (mL). Another way of expressing milliliters is in cubic centimeters (cm3 or cc). Several conversion factors for volume measurements are listed below. 

Mass measurements of objects are carried out with the laboratory balance. Many types of balances are available for laboratory use. The proper choice of a balance depends upon what degree of accuracy is needed for a measurement. The standard units of mass are the kilogram (kg) in the SI system and the gram (g) in the metric system. Some conversion factors are listed below. 

The conversion factor approach is quite useful with metric problems. (If you have not yet worked your way through the conversion factor presentation in Unit 4, you might want to do so now.) The metric conversion factors are ones that you can make yourself using the prefixes in Table 15.1. Examples include... 

In the literature, information is found using different systems of units metric, SI, and the English system. Quotations from the literature are presented in their original form. It would be difficult to change all these units in the book to one system. To assist the reader in converting these units, an appendix is provided with conversion factors for all units found in the text. 

Since 1893, the U.S. basis of length measurement has been derived from metric standards. In 1959, a small refinement was made in the definition of the yard to resolve discrepancies both in this country and abroad which changed its length from 3600/3937 m to 0.9144 m exactly. This resulted in the new value being shorter by two parts in a million. At the same time, it was decided that any data in feet derived from and published as a result of geodetic surveys within the U.S. would remain with the old standard (1 ft = 1200/3937 m) until further decision. This foot is named the U.S. survey foot. As a result, all U.S. land measurements in U.S. customary units will relate to the meter by the old standard. All the conversion factors in this table for units referenced to this footnote are based on the U.S. survey foot rather than on the international foot. 

A conversion factor (see below) is used when working with English engineering units no factor is necessary for SI metric units. For a given impeller geometry, the power number is a constant for conditions of turbulent agitation. Values of turbulent power numbers for some agitator impellers are shown in Fig. 12.1. 

This section is abstracted from the official AlChE publication, "SI for AlChE," prepared by the AlChE Metrication Committee in 1979. Units and symbols, prefixes, usage format and conversion factors are included. AlChE mandated that SI units be used in all publications and presentations. Such units are used exclusively in this Handbook. 

Dimensional analysis is the method to convert a number from one unit to another using a conversion factor. Conversion factors establish a relationship of equivalence in measurements between two different units. Examples of conversion factors are tabulated in Table 3.1 (metric prefixes) and Table 3.3 (common conversion factors). 

The metric system problem, part (a), can be solved without paper and pencil— by moving the decimal point in 5.200 three places to the right. The English system conversion, part (b), requires that we remember the number of yards per mile (harder than the 1000 m/km metric conversion factor) and that we use pencil and paper or a calculator to do the arithmetic. The conversion factor 1000 is used for kilograms, kilohters, kilowatts, and any other factor involving the prefix kilo-. The English conversion factor 1760 yd/mile is not used in any other conversion. 

To convert a value expressed in a primary metric unit to its equivalent in a subunit, or vice versa, use a conversion factor with a 1 in front of the subunit and the equivalent value in front of the main unit. Note that either the prefix abbreviation or its equivalent is in front of the symbol for the primary unit ... 

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