Mole, molarity

The Mole, Molar Mass, and Mole-Gram Conversions... 

Table 5.6 Structure of olivine compounds (from Smyth and Bish, 1988). Molar volnme is expressed in cm /mole molar weight in g/mole density in g/cm cell edges and cell volume are in A and A, respectively.

Table 5.33 Structure of pure pyroxene components in stable state. Molar volume in cm l mole molar weight in g/mole cell edges in A cell volume in A. Adapted from Smyth and Bish (1988). ...

In geochemistry, the solubilities of gaseous species in melts are usually expressed through Henry s constant or as fractional solubilities in moles (molar fraction of gaseous species in the gas phase over molar fraction of gaseous species in the melt). 

Notice that you cannot use the unit gram here. The coefficients do not refer to weighing but rather to counting. Once again, the mole-molar mass relationship is involved. 

A more useful way to describe a concentration is molarity. Molarity (M) expresses the number of moles of solute per liter of solution. A 0.1 M NaOH aqueous solution has 0.1 mol of solute (NaOH) in 1 L of water. Because stoichiometric calculations require moles, molarity is more frequently used in calculations. 

The MMA homopolymer and the unreacted PVA are removed from the reaction product by the selective extraction method. The grafted branch PMMA is separated from the backbone by oxidative cleavage of all 1,2-glycols of PVA (about 2 mole%) Molar masses of the isolated graft copolymers and the separated branches are osmo-metrically determined, after acetylation of hydroxyl groups in benzene. The diem-ical composition of the graft copolymers is determined frcan the s onification value of the acetylated sample. 

P = absolute pressure of a gas V(V) = volume (volumetric flow rate) of the gas (h) = number of moles (molar flow rate) of the gas... 

Number of chemical species, phase rale Avogadro s number Number of moles Molar flowrate... 

Formulating models A nuclear model of mass can provide a simple picture of the connections between the mole, molar mass, and the number of representative particles in a mole. 

Then, moles of S2CI2 is converted to grams of S2CI2 by multiplying by the conversion factor that relates mass and moles, molar mass. 

Heat capacity Cp is defined as the energy required to change the temperature of a unit mass (specific heat) or mole (molar heat capacity) of the material by one degree. Typical units are J/(kg K). 

We often express the volume of a solution in milliliters rather than in liters. Likewise, we may express the amount of solute in millimoles (mmol) rather than in moles. Because one milliliter is 1/1000 of a liter and one millimole is 1/1000 of a mole, molarity also may he expressed as the numher of millimoles of solute per milliliter of solution ... 

Nomenclature Oxidizing power electrons transfeired/mole Molar wt. g/mole Equiv. wt. per electron transferred Oxidizing power relative to chlorine... 

In the preceding sections, the stoichiometric relationships used to quantify the operation of chemical reactors were expressed in terms of extensive quantities (moles, molar flow rates, reaction extents, etc.) whose numerical values depend on the basis selected for the calculation. In most applications, it is convenient to define intensive dimensionless quantities that characterize the operation of chemical reactors and provide quick measures of the reactor performance. In this section, we define and discuss some common stoichiometric quantities used in reactor analysis. 

The three most common problems that involve the mole, molar mass, and numbers of atoms, as they apply to elements, are discussed in the three following sections. As each problem is put forth, keep in mind that the methods used to solve them will also be applied to compounds later in the chapter. Each problem is discussed in greater detail here to ensure that you understand the principles. 

If you answered incorrectly, review Elements and the Mole—Molar Mass, page 111. 

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