Mass- and Volume-Based Concentration

Dissolve 5.4 g of Tris base and 2.75 g of boric acid in 700 ml of distilled water. Add 2 ml of 0.5 M EDTA, pH 8.0. Bring the final volume of the solution to 1 liter with distilled water. NOTE A 5x concentrated stock can be prepared and stored at room temperature for a short time by multiplying all of the masses and volumes of the Tris base, boric acid, and EDTA components by 10. This 5x concentrated stock will be diluted 1 10 with distilled water to give a 0.5x working solution. 

Oxygen transfer rate (OTR) The product of volumetric oxygen transfer rate kj a and the oxygen concentration driving force (C - Cl), (ML T ), where Tl is the mass transfer coefficient based on liquid phase resistance to mass transfer (LT ), a is the air bubble surface area per unit volume (L ), and C and Cl are oxygen solubility and dissolved oxygen concentration, respectively. All the terms of OTR refer to the time average values of a dynamic situation. 

To convert between molarity and the other mole-based concentration measures, we must relate volume to mass and number of moles. Whereas molar mass lets us convert between mass and moles, we need density to convert... 

C18-0013. Determine the mass of solid sodium formate (NaHC02) and the volume of 0.500 M HCl solution required to generate 250 mL of buffer solution with pH = 3.50 and a total concentration (conjugate acid plus base) of 0.225 M. 

In the above equalitms, Kl is the overall mass transfer coefficient (based on phase L), a is the specific interfacial area for mass transfer related to unit column volume, X and Y are the phase solute concentrations, X is the... 

This means that representing the equilibrium adsorbate mass (or volume) adsorbed versus concentration (or partial pressure) should be a straight line if plotted on logarithmic scales. Other theoretically based correlating equations are available for the adsorption of gases and vapors9, but all equations have their limitations. 

The amount of a substance present in a given mass or volume of another substance. The abbreviations w/w, w/v and v/v are sometimes used to indicate whether the concentration quoted is based on the weights or volumes of the two substances. Concentration may be expressed in several ways. These are shown in Table 1.2. 

Model simulations of particle volume concentrations in the summer as functions of the particle production flux in the epilimnion of Lake Zurich, adapted from Weilenmann, O Melia and Stumm (1989). Predictions are made for the epilimnion (A) and the hypolimnion (B). Simulations are made for input particle size distributions ranging from 0.3 to 30 pm described by a power law with an exponent of p. For p = 3, the particle size distribution of inputs peaks at the largest size, i.e., 30 pm. For p = 4, an equal mass or volume input of particles is in every logaritmic size interval. Two particle or aggregate densities (pp) are considered, and a colloidal stability factor (a) of 0.1 us used. The broken line in (A) denotes predicted particle concentrations in the epilimnion when particles are removed from the lake only in the river outflow. Shaded areas show input fluxes based on the collections of total suspendet solids in sediment traps and the composition of the collected solids. 

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