Molar concentration calculating

Sodium chloride has a relative molecular mass of 58.44. A 0.1000M solution is prepared by weighing out 2.922 g of the pure dry salt (see Section 10.74) and dissolving it in 500 mL of water in a graduated flask. Alternatively about 2.9 g of the pure salt is accurately weighed out, dissolved in 500 mL of water in a graduated flask and the molar concentration calculated from the weight of sodium chloride employed. 

The agreement is excellent up to a 1 molar concentration. The excess energies for 1-1, 2-1, 2-2 and 3-1 charge types calculated from the MS and HNC approximations are shown in figure A2.3.13. The Monte Carlo... 

Calculate the molar concentration of NaCl, to the correct number of significant figures, if 1.917 g of NaCl is placed in a beaker and dissolved in 50 mF of water measured with a graduated cylinder. This solution is quantitatively transferred to a 250-mF volumetric flask and diluted to volume. Calculate the concentration of this second solution to the correct number of significant figures. 

A quantitative solution to an equilibrium problem may give an answer that does not agree with the value measured experimentally. This result occurs when the equilibrium constant based on concentrations is matrix-dependent. The true, thermodynamic equilibrium constant is based on the activities, a, of the reactants and products. A species activity is related to its molar concentration by an activity coefficient, where a = Yi[ ] Activity coefficients often can be calculated, making possible a more rigorous treatment of equilibria. 

Calculate the molar concentration for the underlined component in the following cell if the cell potential is measured at +0.294 V... 

Of course, you should be familiar with this equation (the Ideal Gas Law), where n is the molar concentration of solute, R is the universal gas law constant, and T is absolute temperature in °K. The permeate flow can be calculated from ... 

The standard state chosen for the calculation of controls its magnitude and even its sign. The standard state is established when the concentration scale is selected. For most solution kinetic work the molar concentration scale is used, so A values reported by different workers are usually comparable. Nevertheless, an important chemical question is implied Because the sign of AS may depend upon the concentration scale used for the evaluation of the rate constant, which concentration scale should be used when A is to serve as a mechanistic criterion The same question appears in studies of equilibria. The answer (if there is a single answer) is not known, though some analyses of the problem have been made. Further discussion of this issue is given in Section 6.1. 

Notice that the piO, value shown in Table 2.3 for water is 15.74, which results from the following calculation the Ka for any acid in water is the equilibrium constant /vet) for the acid dissociation multiplied by 55.4, the molar concentration of pure water. For the acid dissociation of water, we have... 

As an example we may calculate the e.m.f. of the Daniell cell with molar concentrations of zinc ions and copper(II) ions ... 

Calculation of the molarity. In this particular case the molar concentration is readily calculated from the simple relationship ... 

Calculation of molar concentration. This is similar to that described in Section 10.25. The R.M.M. of potassium hydrogenphthalate is 204.22. The variation in the results should not exceed 0.1 0.2 per cent. 

Calculate the molar concentration of the silver nitrate solution. 

Take 10 mL of commercial propan-2-ol and dilute to 100 mL with carbon tetrachloride in a graduated flask. Record the infrared spectrum and calculate the absorbance for the peak at 1718 cm-1. Obtain a value for the acetone concentration from the calibration graph. The true value for the acetone in the propan-2-ol will be 10 times the figure obtained from the graph (this allows for the dilution) and the percentage v/v value can be converted to a molar concentration (mol L-1) by dividing the percentage v/v by 7.326 e.g. 1.25 per cent v/v = 1.25/7.326 = 0.171 molL-1. 

Fig. 6. Dependence of relative molar concentrations Wj/nA0 of reaction components on reciprocal space velocity W/F (hr kg mole-1) in the consecutive demethylation of m-xylene. Temperature 330°C, catalyst Ni-AljOs (55% wt. AljOs), initial molar ratio of reactants 0 = 5. The curves were calculated (1—xylene, 2—toluene, 3—benzene) the points are experimental values.

Calculated from the data of Hferisson and Chauvin 88, Table 1) the numbers represent relative molar concentrations. 

Calculate the molar concentration (molarity) of a solute from titration data (Toolbox L.2 and Example L.2). 

What Do We Need to Know Already The concepts of chemical equilibrium are related to those of physical equilibrium (Sections 8.1-8.3). Because chemical equilibrium depends on the thermodynamics of chemical reactions, we need to know about the Gibbs free energy of reaction (Section 7.13) and standard enthalpies of formation (Section 6.18). Ghemical equilibrium calculations require a thorough knowledge of molar concentration (Section G), reaction stoichiometry (Section L), and the gas laws (Ghapter 4). 

The overall strategy for finding the relation between K and Kc is to replace the partial pressures that appear in K by the molar concentrations and thereby generate Kc. For this calculation, we write activities as Pj/P° and [J]/c° and track the units by keeping P° and c° in our expressions. 

For thermodynamic calculations, gas-phase equilibria are expressed in terms of K but, for practical calculations, they may be expressed in terms of molar concentrations by using Eq. 12. 

Self-Test 12.12A Calculate the molar concentration of Y1H in a saturated solution of YF3 by using a cell constructed with two yttrium electrodes. The electrolyte in one compartment is 1.0 M Y(NO ),(aq). In the other compartment you have prepared a saturated solution of YF3. The measured cell potential is +0.34 V at 298 K. 

To set up expressions for the instantaneous rate of a reaction, we consider At to be very small so that t and t + At are close together we determine the concentration of a reactant or product at those times and find the average rate from Eq. 1. Then we decrease the interval and repeat the calculation. We can imagine continuing the process until the interval At has become infinitely small (denoted d/) and the change in molar concentration of a reactant R has become infinitesimal (denoted d R]). Then we define the instantaneous rate as... 

Solution Aside from the temperature calculations, this example illustrates the systematic use of mass rather than molar concentrations for reactor... 

Dynamic differential equation balances were written to calculate the molar concentration of each species in the reactor. These equations consist of inflow, outflow, accumulation, and reaction terms for a CSTR. If there are no outflow terms, the equations reduce to semibatch... 

Molar concentrations in millimoles (quantities in parentheses are total ionic strengths calculated from Equation 4), (O) 0.22mM 0.55mM SLS (V) l.OSmM SLS (0 )... 

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