Sodium chloride formula weight

Pure sodium chloride, like pure water, has a definite melting (freezing) temperature (at a given pressure). Separating operations—such as distilling or freezing—do not separate the salt into components. The composition of the salt, whether expressed in relative numbers of sodium and chlorine atoms or in the relative weights of these atoms, is fixed and is represented by the formula NaCl. Sodium chloride, like water, is an example of a pure substance. 

For nonmolecular substances like sodium chloride, the use of the word mole, with its connotation of molecules, is inappropriate. A comparable unit, the gram formula weight, is used it is defined as the sum in grams of the atomic weights of all the atoms in the chemical formula of the substance. For sodium chloride (NaCl), one gram formula weight is calculated as... 

Molecular weights.—The composition of the alkali chlorides has been established by analyses. These salts contain alkali, R, and chlorine, Cl, in the proportion 1 1. Consequently, the mol. formulse are represented by RnCln. The difficult volatility of sodium chloride—contrasted with say mercuric chloride—suggests a complex molecule. W. Nernst 78 found the vapour density of both sodium and potassium chlorides, at 2000°, corresponded with the respective formula NaCl and KC1 for the vapours of these salts. L. Riigheimer found that the effect of sodium chloride on the b.p. of bismuth trichloride corresponded with the simple formula NaCl and E. Beckmann obtained a similar result from the effect of sodium, potassium, rubidium, and csesium chlorides on the f.p. of mercuric chloride. 

SODIUM CHLORIDE. NaO. formula weight 58.44, white solid, cubic crystal structure, mp 800.6 C, bp 1,413 C, sp gr 2.165. Commonly called... 

The relative formula mass (RFM) equals the atomic or molecular weight of the substance, so for a compoimd such as sodium chloride (NaCl) this is simply the sum of the atomic weights of Na (23) and Cl (35.5), taken from the Periodic Table of the elements (see Appendix 2). The terms relative formula mass and relative atomic mass are often taken as interchangeable. 

Some substances exist as a collection of ions rather than as separate mol- ecules. An example is ordinary table salt, sodium chloride (NaCl), which is composed of an array of Na+ and Cl- ions. There are no NaCl molecules present. However, in this text, for convenience, we will apply the term molar mass to both ionic and molecular substances. Thus we will refer to 58.44 (22.99 + 35.45) as the molar mass for NaCl. In some texts the term formula weight is used for ionic compounds instead of the terms molar mass or molecular weight. ... 

Molecular Weights. — Since atoms combine to form molecules, a molecular weight is the sum of the weights of the atoms in a molecule. If the molecule is the simple combination of two atoms, then the molecular weight is the sum of the respective atomic weights. Thus experimental evidence points conclusively to the fact that sodium chloride contains one atom of sodium and one atom of chlorine, hence its formula is NaCl and its molecular... 

Because no simple NaCl molecules exist at ordinary temperatures, it is inappropriate to refer to the molecular weight of NaCl or any ionic compound. One mole of an ionic compound contains 6.02 X 1Q23 formula units of the substance. Recall that one formula unit of sodium chloride consists of one sodium ion, Na+, and one chloride ion, Cl . One mole, or 58.4 g, of NaCl contains 6.02 X 1023 ]Sy[2+ 5 q2 x 1023 CC ions (Table... 

Can also be obtained from the stoichiometric quantities of hydroxylammonium chloride, oxalic acid and sodium hydroxide (sufficient for neutralization). A diluted solution of the hydroxylammonium salt (140 g. in 400 ml. of water) is used. All the solid oxalic acid is added at once with vigorous mechanical agitation, and the mixture is neutralized with a solution of 80 g. of NaOH in 200 ml. of HgO. This solution is added in the fastest possible stream of separate drops. The mixture is agitated for 30 minutes, cooled to 15 C, filtered and washed three times with 100 ml. of HgO. Since the salt at this point often contains up to 10% of oxalic acid, it must be recrystallized from eight times its weight of water. The yield is 95 g. the purity is 99%. Formula weight 156.10. 

Salt and Buffer.— All experiments were done iu 0.9% sodium chloride solution, without buffer present unless otherwise noted. When a buffer is referred to as xF it is meant that the sum of all forms of the buffering material is X formula weights per liter. 

For a fixed total volume of the electrolyte, the weight of hydrated metal sulfate, sodium chloride, and volume of sulfuric add can be determined, respectively, using the following formulas... 

We first take a look at ionic solutes, such as sodium chloride (NaCl). As we stated in Chapter 6 (Figure 6.21), such compounds do not exist as molecules but rather as formula units in a three-dimensional (3-D) array of ions. That is why we refer to formula units rather that molecules and to formula weights rather than molecular weights. 

Standard EDTA Solutions. Di sodium dihydrogen ethylenediaminetetraacetate dihydrate is available commercially of analytical reagent purity. After drying at 80°C for at least 24 hr, its composition agrees exactly with the dihydrate formula (molecular weight 372.25). It may be weighed directly. If an additional check on the concentration is required, it may be standardized by titration with nearly neutralized zinc chloride or zinc sulfate solution. 

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