Calculating molarity from

EXAMPLE G.l Calculating molarity from the mass of solute... 

Calculating molarity From the experimental data, the molarity of the unknown HCOOH solution can be calculated by following these steps. 

Thus, the dissolved molar amount Uj can be easily obtained by subtracting the previously calculated molarities. From this value, the calculation of the activity coefficient is done analogous to that in Section 9.2.1.1. 

Calculating molarity from mass and volume Given the... 

EXAMPLE 4-7 Calculating Molarity from Measured Quantities... 

The molarity of the solution can be calculated directly from the weight of salt taken, but if the salt has only been weighed out approximately, then the solution must be standardised as described in the following section. 

For any aqueous strong base, the hydroxide ion concentration can be calculated directly from the overall solution molarity. As is the case for aqueous strong acids, the hydronium and hydroxide ion concentrations are linked through the water equilibrium, as shown by Example. ... 

Now calculate the molar enthalpies of the vapor and liquid streams. Enthalpies were calculated here from ideal gas enthalpy data corrected using the Peng-Robinson Equation of State (see Chapter 4) ... 

A standard UV cell was filled with 3.5mL of a 3 X 10"4 M dichloromethane solution of polyether 2. The solution was then treated with 10 uL of trifluoromethanesulfon-ic acid and the changes in UV absorption of the mixture were monitored. Once the reaction was complete the molar extinction coefficient of the product at 276nm was identical to that of naphthalene, therefore conversions during acidolysis were calculated directly from absorption measurements (At/A ). 

In a few, but important, cases, EM s have been calculated not from rate constants but from product ratios. Where the effective molarity is low, competition between intramolecular and intermolecular reactions of the same compound may be observed, as in Freundlich s early work on the cyclization of w-bromoalkylamines (1) described by Salomon (1936). The inter-... 

Several problems arise in the preparation of solutions in nonaqueous solvents. The large thermal coefficient of expansion of many solvents necessitates the use of weight methods to establish concentrations, with subsequent calculation of molarities from weight concentrations. Also, solutions must be prepared and maintained under strictly anhydrous conditions during the course of the experiment. Further, since the preparation of quantities of highly pure solvent is difficult, the use of minimum amounts is desirable. Finally, salts sometimes dissolve very slowly in certain solvents, which makes efficient stirring to hasten dissolution important. 

Several methods have been developed for calculating fugacities from measurements of pressures and molar volumes of real gases. 

Figures 2 and 3 present typical results obtained from a low plate count column and a high plate count column. The graphs present the calculated molar concentrations of macromolecular species as a function of their degree of polymerization. The straight lines are the theoretical, kinetic distributions. Inasmuch as convergent solutions are obtained, the algorithm is effective for correction for Imperfect resolution.

Figures 1 to 3 present calculated equilibrium molar ratios of products to reactants as a function of temperature and total pressure of 1 and 100 atm. for the gas-carbon reactions (4), (7), and (5), (6), (4), (7), respectively. Up to 100 atm. over the temperature range involved, the fugacity coefficients of the gases are close to 1 therefore, pressures can be calculated directly from the equilibrium constant. From Fig. 1, it is seen that at temperatures above 1200°K. and at atmospheric pressure, the conversion of carbon dioxide to carbon monoxide by the reaction C - - COj 2CO essentially is unrestricted by equilibrium considerations. At elevated pressures, the possible conversion markedly decreases hence, high pressure has little utility for this reaction, since increased reaction rate can easily be obtained by increasing reaction temperature. On the other hand, for the reaction C -t- 2H2 CH4, the production of methane is seriously limited at one atmosphere pressure and practical operating temperatures, as seen in Fig. 2. Obviously, this reaction must be conducted at elevated pressures to realize a satisfactory yield of methane. For the carbon-steam reaction.

Calculate Da from the empirical relation to molar mass. From Fig. 18.9b follows ... 

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