Concentration by mass

Note Elements in order of decreasing concentration by mass. 

Solute mass per unit volume p is a concentration by mass p = CM/ ... 

Concentration by mass corresponding to the cross-over from dilute to semi-dilute p = CqM/ where Cj = (6Ro/tf)-d/2 Pauli matrices Unit matrix 2x2... 

Mms Loss. The amount of the original wood that has been diagenet-ically lost cannot be calculated directly from the measured decrease in the weight percentages of holocellulose (or its components) because all constituents of the remnant material are artificially concentrated by mass loss. 

The atomic mass difference between the radionuclide and the mix of its stable isotopes in nature, although minor in terms of its effect on chemical equilibrium and reaction rates, provides opportunities for separation, identification, and quantification at low concentration by mass spectrometer, as discussed in Chapter 17. The mass difference ratio is at its extreme for tritium (T or H) relative to the stable isotopes and H. This distinction causes minor separation between ordinary water with molecular mass 18 and tritiated water (HTO) with molecular mass 20 during distillation, and can be applied to enriching tritiated water in the laboratory by electrolysis. 

Let us consider the isotopic exchange between X (normal) and X (labeled) atoms in diatomic molecules X2, where X = or and X = H or 0. The measurement of the change in X2, XX and X2 concentrations, by mass spectrometry, as a function of kinetic parameters (e.g., time, temperature, partial pressure) allows the determination of ... 

Use of Equation (2.8) assumes knowiedge of two constants (exduding densities) shiny concentration by mass fiuction and filter cake concentration by volume firaction. The... 

Solid Concentration (% by mass) Suspension Density (kg m-3) Flow Index Consistency Coefficient... 

Nitric acid is usually purchased in concentrated form with a 70.3% HNO3 concentration by mass and a density of 1.41 g/mL. How much of the concentrated stock solution in milliliters should you use to make 2.5 L of 0.500 M HNO3 ... 

All of the solution concentration units introduced in this chapter are direct proportionalities. Percentage concentration by mass is a direct proportionality between mass of solute and mass of solution molarity, between moles of solute and liters of solution molality, between moles of solute and kilograms of solvent and normality, between equivalents of solute and liters of solution. These proportional relationships allow you to think of solution concentration units as conversion factors between the two units in the fraction. Do you know mass of solution and need mass of solute Use percentage concentration. Do you know volume of solution and need moles of solute Use molarity. Thinking about solution concentration units in this way allows you to become more skilled at solving quantitative problems. 

Given a solution of known percentage concentration by mass, a laboratory worker can often measure out a calculated mass of the solution in order to obtain a certain mass of solute. Sometimes, though, it is impractical to use the mass of a solution, especially with fuming solutions, such as concentrated HCl and concentrated HNO3. Measuring these solutions by volume is much more practical. In order to determine the volume that should be measured, a worker would need to know the density of the solution. This information usually appears on the label of the solution bottle. 

Strategy Use the molar mass of glucose to determine the number of moles of glucose in a liter of solution. Use the density Un g/L) to calculate the mass of a liter of solution. Subtract the mass of glucose from the mass of solution to determine the mass of water. Use Equation 13.1 to determine the molality. Knowing the mass of glucose and the total mass of solution in a liter, use Equation 13.2 to calculate the percent concentration by mass. 

The reaction of CINO with F has been used to determine F atom concentrations by mass spectrometric measurement of the CIF produced after the addition of excess CINO. The ClF ion peak was calibrated by the addition of measured quantities of ClF from a cylinder (14). To eliminate the need to work with the reactive CIF gas, a variant of this method was developed in which the F atoms were titrated with ClNO to an endpoint identified as the amount of added CINO beyond which the CIF peak no longer increased ( ). The CINO methods are less well established them some other, inasmuch as the rate constant of reaction (1) has not been determined. Also, at high concentrations, the reaction NO + F2 -> FNO + F, which has a rate constant of 8 x 10 cm molecule" s at 300 K, may occur to an apprecicible extent, leading to an erroneous value for fJ. 

One also regularly sees concentrations by mass (or weight) for example,... 

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