Formula weight mole conversions with

Ans. There are 6.02 X 10 i atoms in 1.00 mol Na (Avogadro s number). There is 23.0 g of Na in LOO mol Na (equal to the atomic weight in grams). This problem requires use of two of the most important conversion factors involving moles. Note which one is used with masses and which one is used with numbers of atoms (or molecules of formula units). With numbers of atoms, molecules, or formula units, use Avogadro s number with mass or weight use the formula weight. 

What does 1 ppm represent in terms of moles per liter It depends on the formula weight, but the approximate relationship between concentrations in parts per million (or parts per billion) and in moles per liter can be seen by assuming a formula weight of 100 for an analyte. Then, since 1 ppm = 10 g/L, it is equal to (10 g/L) (10 g/mol) = 10 mol/L. Similarly, 1 ppb = 10 mol/L. Note that this latter concentration is smaller than the hydrogen ion concentration in pure water (10" mol/L) Of course, this relationship is approximate and will vary with the formula weight. One part per million solutions of zinc and copper, for example, will not be the same molarity. Conversely, equal molar solutions of different species will not be equal in terms of ppm unless the formula weights are equal. The former concentration is based on the number of molecules per unit volume, while the latter is based on the weight of the species per unit volume. 

As we saw with mass and moles of elements and molecular compounds, it is important to be able to convert between mass and moles of ionic substances. The development of the tools for this conversion starts with the determination of the formula mass, which is the weighted average of the masses of the naturally occurring formula units of the substance. (It is analogous to the atomic mass for an element and the molecular mass for a molecular substance.)... 

For the conversion of weight % to mole %in ternary mixtures Lessels [13] gives a useful nomogram. In the case of binary mixtures the various conversions are performed with the following formulae, which all refer to the low-boiling component 1. ... 

Unit conversions and simple data transformations were accomplished with table lookups for unit conversion factors and by algebraic manipulation of the data. As an element of the conversion process, the values were tested to see if they were within reasonable physical limits, for example, were mole fractions greater than 0 and less than 1. Where molecular weights were required, they were determined from molecular formulas in the list of compound names and registry numbers. The requisite data from the DIPPR Project 801 and other compilations such as that by Viswanath Natarajan (1988) were used for testing zero mole fraction results and for possible data renormalization. 

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