Formula subscripts

Molecular formula elemental symbols with subscripts denote the composition of a compound Empirical formula subscripts denote the relative elemental composition... 

Molecular formula subscripts = n x Empirical formula subscripts, where n = 1, 2,3... 

Table 6.2 gives you some strategies for converting subscripts to whole numbers. The variable x stands for any whole number. Examine the following Sample Problem to learn how to convert the empirical formula subscripts to the lowest possible whole numbers. 

The integer from the previous step represents the number of empirical formula units in one molecule. When the empirical formula subscripts are multiplied by this integer, we obtain the molecular formula. 

Formats text, e.g., H2S04, as a chemical formula (subscripts numbers). Operates on a cell, a range of cells, text in a chart, or a textbox. 

Plan The molecular formula subscripts are whole-number multiples of the empirical formula subscripts. To find this whole number, we divide the given molar mass (90.08 g/moI) by the empirical formula mass, which we find from the sum of the elements molar masses. Then we multiply the whole number by each subscript in the empirical formula. Solution The empirical-formula molar mass is 30.03 g/mol. Finding the whole-number multiple ... 

The answer makes physical sense because the formula subscripts are all integers. Any answer with fractional integers would be suspect. 

Multiplying the empirical formula subscripts by 2 gives the molecular formula ... 

The fact that the total positive charge must equal the total negative charge implies a relationship between the charges on the ions and their molal concentrations. For a simple binary salt A +B , where n+ and are the formula subscripts for the cation and anion, respectively, ionic solutions require that the molalities of the cation and anion satisfy the formula... 

Jumping to the symbolic domain requires even more abstract reasoning and, moreover, the use of complex notation conventions. Not surprisingly, this also evokes a lot of difficulties. Students tend to ignore the submicro models that give meaning to chemical symbols (Yarroch, 1985). This can foster students alternative conceptions of formula subscripts and coefficients (see the former section) and will contribute to conceive balancing chemical equations as mainly mathematical manipulations of symbols. 

When balancing chemical equations, why is it permitted to change the numbers in front of a chemical formula (coefficients) but not a number within a chemical formula (subscripts) ... 

Determine the contribution of the given element to the molar mass. This product of the formula subscript and the molar mass of the element appears in the numerator of equation (3.1). 

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