Decimal multiples of SI units

Decimal multiples of SI units are formed by attaching a prefix directly before the unit and a symbol prefix directly before the unit symbol. SI prefixes range from 10 24 to 1024 Only the prefixes you are likely to encounter in chemistry are shown below ... 

The CGPM in 1960 adapted the first series of prefixes and symbols of decimal multiples of SI units. Over the years, the list has been extended to include those listed in Table 6.2. SI is the most common system of units used in the world. 

So-called prefixes can be used in front of SI miits they can be used to form appropriate munerical values, names and symbols for the decimal multiples of SI units. The following prefixes are given in the SI system ... 

SI units Syst me International d Unit s the international system of units now recommended for all scientific purposes. A coherent and rationalized system of units derived from the m.k.s. units, SI units have now replaced c.g.s. units and Imperial units. The system has seven base units and two dimensionless (formerly called supplementary) units (see Appendix), all other units being derived from these nine units. There are 18 derived units with special names. Each unit has an agreed symbol (a capital letter or an initial capital letter if it is named after a scientist, otherwise the symbol consists of one or two lower-case letters). Decimal multiples of the units are indicated by a set of prefixes whenever possible a prefix representing 10 raised to a power that is a multiple of three should be used. 

The International System of Units was devised to facilitate communication between scientific and engineering disciplines. Using SI units is highly recommended because it minimizes errors that arise from complicated units conversions. The International System of Units is based on seven base units (Table 2.1). Decimal multiples of these units and derived units are named using the prefixes listed in Table 2.2. 

Decimal fractions and multiples of SI units are designated by using the prefixes listed in Table 3.2. Those that are most commonly used in general chemistry are in boldface type. 

The revised metric system is called the International System of Units (abbreviated SI, from the French Systeme Internationale d Unitds). Table 1.2 lists the seven SI base units. All other units of measurement can be derived from these base units. The SI unit for volume, for instance, is derived by cubing the SI base unit for length. The prefixes listed in Table 1.3 are used to denote decimal fractions and multiples of SI units. This enables scientists to tailor the magnitude of a unit to a particular application. For example, the meter (m) is appropriate for describing the dimen.sions of a classroom, but the kilometer (km), 1000 m, is more appropriate for describing the distance between two cities. Units that you will encounter frequently in the study of chemistry include those for mass, temperature, volume, and density. 

Rewrite the numerical value 5.4 -10 s to an SI unit in prefix form and rewrite the numerical value 0.023 GJ to a decimal multiple of the unit J ... 

Decimal multiples of the coherent base and derived SI units are formed by attaching to these units the prefixes shown in Table 2. 

In the International System there is only one SI unit for each physical quantity. This is either the appropriate SI base unit itself (see table 3.3) or the appropriate SI derived unit (see tables 3.4 and 3.5). However, any of the approved decimal prefixes, called SI prefixes, may be used to construct decimal multiples or submultiples of SI units (see table 3.6). 

To signify decimal multiples and submultiples of SI units the following prefixes may be used [3]. 

The prefixes listed in Table 16.13 are used to indicate decimal multiples of base and derived SI units. ... 

Decimal multiples and fractions of SI units are designated by prefixes. Those in common use are listed in Table 1.1. Thus we have, for example, that 1 cm = 10" m and 1 kg = 10 g. 

Decimal Multiples and Submultiples of SI Units In practical application of SI units, certain values are too large or too small to be expressed conveniently in the base or derived units. Numerical values can be brought to convenient size when the unit is appropriately modified by official SI prefixes. In general the prefixes are such that the value of the unit changes 1000-fold. However, certain common previously accepted multiples or sub multiples, such as deci- and hecto-, are still accepted in the SI framework. The SI prefixes are listed in Table 1-5 together with their symbols. 

Table 5 gives the SI prefixes that are used to form decimal multiples and submultiples of SI units. They allow very large or very small numerical values to be avoided. A prefix attaches directly to the name of a unit, and a prefix symbol attaches directly to the symbol for a unit. For example, one kilometer, symbol 1 km, is equal to one thousand meters, symbol 1000 m or 10 m. When prefixes are attached to SI units, the units so formed are called "multiples and submultiples of SI units in order to distinguish them from the coherent system of SI units. 

Table A.4 Prefixes used to construct decimal multiples of units (SI).

With SI units, prefixes are used to indicate decimal liractions or multiples of various units. For example, the prefix milH- represents a 10 fraction, one-thousandth, of a unit A milligram (mg) is 10 gram (g), a millimeter (mm) is 10 meter (m), and so forth. TABLE 1.5 presents the prefixes commonly encountered in chemistry. In using SI units and in working problems throughout this text, you must be comfortable using exponential notation. If you are unfamiliar with exponential notation or want to review it, refer to Appendix A.l. 

SI units (SI Systeme fnternational d Unites) The modern coherent rationalized internationally adopted metric system of units. It has seven BASE UNITS and two dimensionless units, formerly called supplementary units. DERIVED UNITS are formed by multiplication and/or division of base units. Standard prefixes are used for decimal multiples and submultiples of SI units, along with standard symbols for both units and prefixes. 

ThelntemationalSystemofUnits(SI),PhysicalQuantities,andTheirDimensions I 2.5 Decimal Multiples and Submultiples of SI Units 19... 

Certain SI derived units have special names and symbols these are given in Table 1-6 Table 1-7 gives the SI prefixes that are used to form decimal multiples and submultiples of SI units. They allow very large and very small... 

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