Looking up values in tables

For an example of using VLOOKUP and MATCH, see "Looking Up Values in Tables" in Chapter 9. 

Lookup2.xls illustrates how to look up values in a two-way table. The data table used in this example is part of the Steam Tables and is reprinted from ASME International Steam Tables for Industrial Use. The information in the table was provided by the National Institute for Standards and Technology (NIST) and is in the public domain. 

Plan (a) We need to write the balanced equation for the combustion of CgHg. We then look up values in Appendix C or in Table 5.3 and apply Equation 5.31 to calculate the enthalpy change for the reaction, (b) We use the molar mass of Q Hg to change the... 

Write both half-reactions as reductions, and then look up the ° values in Table 19-1 ... 

Identification when it is not possible to measure refractive indices. In some circumstances it may be desired to identify substances without removing them from their mother liquor. Direct identification—that is, by measuring properties and looking up the measured values in tables—is not possible, and the evidence obtainable is con-... 

To calculate A S° for the reaction, subtract the standard molar entropies of all the reactants from the standard molar entropies of all the products. Look up the S° values in Table 17.1 or Appendix B and remember to multiply the S° value for each substance by its coefficient in the balanced chemical equation. 

I used these tables of Preul for the first part of my doctoral work. The computation of integrals for a valence bond treatment of the H-F molecule on a mechanical desk calculator was greatly simplified by the fact that I could look up values for the required auxiliary functions in these tables. Toward the end of this work (1962-1963), I got access to the electronic computer Z23, which of course could perform the calculations in a much shorter time with much higher accuracy. 

Step 3 Write the ionization constant expression in terms of the equihbrium eoneentrations. Knowing the value of the equilibrium eonstant (K ), solve forx. You ean look up the value in Table 15.3 of the text. 

In this example four protic solutes are considered benzoic acid (BA), phenyl-acetic acid (PAA), phenylsuccinic acid (PSA), and 4-l droxybenzoic acid (HBA). For these optimizations, knowing the pA, value for each solute is he fiil. Here the values are [68] 4.20 for BA, 4.58 for HBA, 4.31 for PAA, and 3.78/5.55 for PSA (diprotic). The pH of the mobile phase (at least the aqueous component) is made to cover the range of at least 1 pH unit of the pAj extremes (here 1.7 and 6.9). Table 2.2 lists the k values generated at each pH and then lists all the ratios calculated therefrom. Note that the ratio is always set up so that the first calculated value is > 1 (i.e., solute 1 is better retained than solute 2). That does not mean that the ratio will remain > 1 throughout the experimental pH range. In fact, looking at the k ratio values in Table 2.2 shows two instances where the ratio goes to < 1. Where this happens, a reversal of elution order has occurred. 

Strategy Write the dissociation equation for Cu(OH)2, and look up its value in Table 17.4. Solve... 

When looking up entropy values in tables of data, we need to choose the data for the correct state, solid, liquid or gas. 

Strategy Write the dissociation equation for Cu(OH)2, and look up its value in Table 17.4. Solve for molar solubility using the equilibrium expression. Convert molar solubility to solubility in g/L using the molar mass of Cu(OH)2. 

Strategy For each part, identify the compound that might precipitate and look up its K p value in Table 17.4 or Appendix 3. Determine the concentrations of each compound s constituent ions, and use them to determine the value of the reaction quotient, Q p then compare each reaction quotient with the value of the corresponding K p. If the reaction quotient is greater than K p, a precipitate wiU form. 

In elementary thermodynamics courses we generally solve problems for devices and systems, processing pure species, looking up values of v, /z, and 5 in suitable tables. In this book we are mostly concerned with mixtures, and how we compute the equivalent of those tables of thermodynamic properties for mixtures. 

State 1 is completely constrained. Looking up values for internal energy in the steam tables for saturated water pressure (Appendix B.2) gives ... 

The actual computation is broken down into two steps (1) A Collision Step, during which the value of a site is sent to a computation look-up table, with its input written to the display screen memory as in CAM-6. RAPl s screen memory consists of 16 256 x 512 planes, (2) A Propagation Step, during which the system is decomposed into a set of one-bit two-dimensional planes (one plane for each bit of each site), and the bits of each site are displaced to one of the site s neighbors by a translation of the entire plane. 

Each program includes the necessary algorithms to generate t-, p-, z-, F-, or X -values (relative errors below 1% for details, see (Display Accuracy) options in program CALCVAL. Therefore, table-look-up is eliminated. 

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