Sl/non-SI conversion factors

As with many things in life, chemistry isn t always as easy as it seems. Chemistry teachers are sneaky They often give you quantities in non-Sl units and expect you to use one or more conversion factors to change them to SI units — all this before you even attempt the hard part of the problem We re at least mcirginally less sneaky than your typical chemistry teacher, but we hope to prepare you for such deception, so expect to use conversion factors throughout the rest of this book ... 

Units and Conversion Factors (all SI units or permitted non-Sl units except those marked with an asterisk)... 

The following table gives conversion factors from various units of measure to SI units. It is reproduced from NIST Special Publication 811, Guide for the Use of the International System of Units (SI). The table gives the factor by which a quantity expressed in a non-Sl unit should be multiplied in order to calculate its value in the SI. The SI values are expressed in terms of the base, supplementary, and derived units of SI in order to provide a coherent presentation of the conversion factors and facilitate computations (see the table International System of Units in this Section). K desired, powers of ten can be avoided by using SI Prefixes and shifting the decimal point if necessary. 

Most measurements in chemistry are made in SI units. Sometimes we must convert between SI units, as when converting kilometers to meters. At other times we must convert measurements expressed in non-Sl units into SI units, or from SI units into non-Sl units. In all these cases, we can use a conversion-factor or a series of conversion factors in a scheme called a conversion pathway. Later in this chapter, we will apply conversion pathways in a method of problem solving known as dimensional analysis. The method itself is described in some detail in Appendix A. 

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