Solutions concentration conversion formulas

TABLE 11.5 Conversion Formulas for Solutions Having concentrations expressed in Various Ways... 

Here is a short example showing this. For the titration of 25 mL of sulfuric acid, 20.35 mL of sodium hydroxide solution (0.1 mol L ) is consumed. We are looking for the concentration of the acid. The conversion formula for this is... 

Conversion Formulas for Concentration of Solutions Electrochemical Series... 

Molarity (M) A concentration unit defined to be the number of moles of solute per liter of solution, 95q, 259 concentration unit conversion, 261-262 potassium chromate, 263 Mole A collection of6.0122 X 1023 items. The mass in grams of one mole of a substance is numerically equal to its formula mass, 55. See also Amount Mole fraction (X) A concentration unit defined as the number of moles of a component divided by the total number of moles, 116-117,261 Mole-gram conversions, 55-56,68-68q... 

Again, conversion factors are the way to approach these kinds of problems. Each problem features a certain volume of solution that contains a certain solute at a certain concentration. To begin each problem, convert your volume into liters — part (c) has already done this for you. Then rearrange the molarity formula to solve for moles ... 

These have only one true stationary-state solution, ass = pss = 0 (as t - go), corresponding to complete conversion of the initial reactant to the final product C. This stationary or chemical equilibrium state is a stable node as required by thermodynamics, but of course that tells us nothing about how the system evolves in time. If e is sufficiently small, we may hope that the concentrations of the intermediates will follow pseudo-stationary-state histories which we can identify with the results of the previous sections. In particular we may obtain a guide to the kinetics simply by replacing p by p0e et wherever it occurs in the stationary-state and Hopf formulae. Thus at any time t the dimensionless concentrations a and p would be related to the initial precursor concentration by... 

Kirste and Lehnen2 determined the Z average of the square radius of gyration, Rg, z of the long chain, in the limit of zero concentration, using the classical interpolation formula (15.5.3) see also Fig. 15.1. (The more adequate formula (15.5.4) was unknown to them.) In an earlier experiment, they also measured the Z average of the square radius of gyration, °Rg,z< of the same chains in the quasi-Brownian state this is the state in which polydimethyl-siloxane chains are found when dispersed in dilute solution in bromo-cyclohexane at temperature T (29 °C). The authors quoted above obtained °Rg,z — 125.44 nm2, i.e. an equivalent area 5, 2(°/ g,z) = 250.88 nm2. From this value, we get the conversion factor [see (15.2.1)]... 

What does 1 ppm represent in terms of moles per liter It depends on the formula weight, but the approximate relationship between concentrations in parts per million (or parts per billion) and in moles per liter can be seen by assuming a formula weight of 100 for an analyte. Then, since 1 ppm = 10 g/L, it is equal to (10 g/L) (10 g/mol) = 10 mol/L. Similarly, 1 ppb = 10 mol/L. Note that this latter concentration is smaller than the hydrogen ion concentration in pure water (10" mol/L) Of course, this relationship is approximate and will vary with the formula weight. One part per million solutions of zinc and copper, for example, will not be the same molarity. Conversely, equal molar solutions of different species will not be equal in terms of ppm unless the formula weights are equal. The former concentration is based on the number of molecules per unit volume, while the latter is based on the weight of the species per unit volume. 

Conversely, at concentrations which are less than the optimal one we decrease the efficiency with striving for a more monodisperse sample. Since the molecular mass is unambiguously related to the size of macromolecules (formula 3), one can assume that the dependences for the dispersion coefficient plotted according to the size of macromolecules will be similar. In ref. [5] the mechanism for destruction of polymer solutions was studied, where one of the basic aims was an attempt to find out what happens to macromolecules during the dest-... 

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