MF

The momentum and continuity equations give rise to a 22 x 22 elemental stiffness matrix as is shown by Equation (3.31). In Equation (3.31) the subscripts I and / represent the nodes in the bi-quadratic element for velocity and K and L the four corner nodes of the corresponding bi-linear interpolation for the pressure. The weight functions. Nr and Mf, are bi-qiiadratic and bi-linear, respectively. The y th component of velocity at node J is shown as iPj. Summation convention on repeated indices is assumed. The discretization of the continuity and momentum equations is hence based on the U--V- P scheme in conjunction with a Taylor-Hood element to satisfy the BB condition. 

Solubility is given in parts by weight (of the formula weight) per 100 parts by weight of the solvent (i.e., percent by weight) and at room temperature. Another unit frequently used is grams per 100 mF of solvent (mF per 100 mF for liquids and gases). The symbols of the common mineral acids represent aqueous solutions of these acids. 

Calculate the molarity of a potassium dichromate solution prepared by placing 9.67 g of K2Cr207 in a 100-mF volumetric flask, dissolving, and diluting to the calibration mark. 

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. 

To determine the concentration of ethanol in cognac a 5.00-mF sample of cognac is diluted to 0.500 F. Analysis of the diluted cognac gives an ethanol concentration of 0.0844 M. What is the molar concentration of ethanol in the undiluted cognac ... 

What must a solute s distribution ratio be if 99% of the solut in a 50.0-mF sample is to be extracted with a single 50.0-mF portion of an organic solvent Repeat for the case where two 25.0-mF portions of the organic solvent are used. 

A weak acid, HA, with a fQ of I.O X 10, has a partition coefficient, Rp, between water and an organic solvent of I20( What restrictions on the sample s pH are necessary to ensure that a minimum of 99.9% of the weak acid is extracted in a single step from 50.0 mF of water using 50.0 mF of the organic solvent ... 

A sample contains a weak acid analyte, HA, and a weak acid interferent, HB. The acid dissociation constants and partition coefficients for the weak acids are as follows Ra.HA = 1.0 X 10 Ra HB = 1.0 X f0 , RpjHA D,HB 500. (a) Calculate the extraction efficiency for HA and HB when 50.0 mF of sampk buffered to a pH of 7.0, is extracted with 50.0 mF of the organic solvent, (b) Which phase is enriched in the analyte (c) What are the recoveries for the analyte and interferent in this phase (d) What is the separation factor (e) A quantitative analysis is conducted on the contents of the phase enriched in analyte. What is the expected relative erroi if the selectivity coefficient, Rha.hb> is 0.500 and the initial ratio ofHB/HA was lO.O ... 

Each of these titrations was conducted on a 50.00-mF aliquot of the original 250.0-mF sample. The mass of each analyte, therefore, must be corrected by multiplying by a factor of 5. Thus, the grams of Ni, Fe, and Cr in the original sample are... 

This represents the amount of Na2S203 in a 10.00-mF portion of a 100-mF sample, thus 0.1325 g of Na2S203 is present in the original sample. The purity of the sample, therefore, is... 

The most common mobile phases for GC are He, Ar, and N2, which have the advantage of being chemically inert toward both the sample and the stationary phase. The choice of which carrier gas to use is often determined by the instrument s detector. With packed columns the mobile-phase velocity is usually within the range of 25-150 mF/min, whereas flow rates for capillary columns are 1-25 mF/min. Actual flow rates are determined with a flow meter placed at the column outlet. 

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