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ETC■■■THE SOLUTIONS CALCULATOR ■0100 │ ƒ6 Solutions Solve for variables of chemical solutions. │ The SOLUTIONS CALCULATOR is a pre-programmed calculator for dealing with the complex relationships of variables in chemical solutions. The calculator manipulates 17 solution variables and contains 52 pre-programmed equations. By permuting the equations and recalculating with one or more new values you can calculate any needed value to prepare solutions or to design a solution with specific parameters. Solvent values can be imported from the Solvent Guide. Solution values can be calculated for a dilution procedure by exchanging values with the Dilution Calculator. Press the up and down arrow keys to select an equation result (the value you wish to calculate). Use the left and right arrow keys to find the array of inputs matching your known parameters. The actual equation is displayed above the list of variables. The shorthand symbols used in the equation are displayed in the variable list. To start the "Solutions" chemical solutions calculator function from the main menu, press "S" or [ƒ6] or select with the highlight bar and press enter or with your mouse, double-click the menu line. ________________________________________________________________________________ ■0805 SOLVING A CHEMICAL SOLUTION EQUATION When you find the equation which you wish to solve, begin data entry by pressing [enter]. The first data field prompt will be displayed. Enter the value in the units indicated; press [enter] to accept each value. To enter a molecular weight, you can enter a numeric value or, if you wish, type the chemical formula. ü The Molecular Calculator is automatically called for formula entry in the molecular weight fields if you begin entry of a formula instead of entering a numeric value. α When all knowns of the equation have been supplied, the equation will be solved and the answer displayed in the left column. If you are missing a known value for the equation you wish to solve, solve first for that variable with another equation then, retaining that value, re-select your original equation and complete the solution.é You can redo an equation, retaining current values in any fields and substituting new values where desired. Press [enter] to restart data entry. Press [enter] again to accept and retain a current field or type in a new value. ________________________________________________________________________________ »üAutomatic Molecular Weight Calculation If you begin typing a formula, the molecular weight calculator function is activated. When you complete the formula by pressing [enter], the molecular weight is calculated and placed in the data field. ________________________________________________________________________________ »αThe Molecular Weight Calculator ≈400 ÷MLWEIGHT.ISD For more information about the Molecular Weight calculating function, press Y or click on YES to turn to the section of this guide covering the use of the Molecular Weight Calculator. Press or click anything else to close this link. ________________________________________________________________________________ »éChaining Equations If you discover that you do not have known values for all variables, click on the variable you are missing until you find an equation for that variable that you can solve. Then click on your original unknown to return to the equation using the newly calculated known value. ________________________________________________________________________________ ■0810 SOLUTION CALCULATOR MENU In spite of the complex relationship between the 52 equations contained in the Solutions Calculator, it is extremely simple to use. Select your equation by first finding your unknown variable, then choose the formula which solves for it, input your knowns and the result is calculated immediately. ╔═══════════════════════════════════════════════╗ ║ up/down arrows select the result ║ ü Select the desired ║ left/right arrows select knowns ║ é equation. ║ [enter] begin data input ║ â Enter known values. ║ pgup/pgdn permute the equation ║ ä Re-arrange equation. ║ [ins] reveal all current values ║ à See all current data. ║ [del] erase all current values ║ å Start over. ║ [alt∙ƒ5] print report ║ α Print or save. ╚═══════════════════════════════════════════════╝ ________________________________________________________________________________ »üSelect The Results Using the up and down arrow keys or by clicking on the variable with your mouse, highlight the unknown for which you wish to solve. ________________________________________________________________________________ »éSelect Knowns With the left and right arrow keys, or by clicking on the highlighted unknown, examine the available equations to find the one for which you can supply all known values. If you are missing a known value, see the technique for chaining as explained on the previous page. ________________________________________________________________________________ »âInput Data Press [enter] to begin prompting for the known values of an equation. The values will be prompted in order and when they all have been entered the equation will be solved. You can repeat the value entry as you wish, changing values as desired or even permuting to solve for a different unknown. ________________________________________________________________________________ »äPermuting An Equation You can permute an equation, either before or after solving it, by pressing [PgUp] and [PgDn]. Permute a solved equation, entering alternate values where desired. The currently selected unknown will be calculated when all knowns are either accepted or altered. ________________________________________________________________________________ »àReveal All Values Existing values are retained when you select a new equation. That a parameter contains a value is shown by an asterisk in the far right column. When you accept a new equation and begin data entry, compatible values are retained. Values incompatible with the new equation relationships are erased. To reveal the actual value of these carry-overs, press the insert key. ________________________________________________________________________________ »åDelete All Values To erase all current values and begin a new equation with no carry-over values, press the delete key. ________________________________________________________________________________ »αThe Report Utility ≈1310 ÷IS_INTRO.ISD To export a report of the calculated solution to a file or printer, press [@ƒ5]. An input window will open. To learn more about the report generator, press Y or click on YES to turn to that section. Press any other key to close this link. _______________________________________________________________________________ ■5805 USING THE SOLUTIONS CALCULATOR THE SOLUTIONS CALCULATOR SCREEN The Solutions Calculator screen is divided into an upper and lower section. The upper section contains instructions and, just above the dividing line, the current equation formula. The lower section lists the seventeen parameters of a chemical solution used in the equations which the solutions calculator solves. SELECTING THE UNKNOWN The unknown is the value for which the equation will solve. The solution parameters are grouped as properties of the solution, the solvent and the solute. Use the up and down arrow keys to move the unknown selector bar or click on the desired unknown with your mouse. ~ ~> As an example, press the down arrow key until solution density is < ~> selected as the unknown. < CHOOSING AN EQUATION After selecting the value for which to solve, choose the equation consisting of known properties for which you have values by pressing the left and right arrow keys or clicking on the selected unknown. Some unknowns have only a single equation available, but most have several. Click or press until the set of knowns you can supply is highlighted. As the knowns are highlighted, the equation is displayed just above the section line. The symbols used in the equation are also shown next to the selected knowns and unknown. ~ ~> To continue our example; press the left or right arrow keys until < ~> solution volume, solute percent and solute mass are selected as the < ~> knowns. < ENTERING THE KNOWNS When you have selected a formula, enter the known values. Begin data entry by pressing [enter] to reveal the first data prompt, or just begin data entry from the keyboard. ~ ~> In our example, you know that the solution volume is 625 ml, the < ~> mass of solute is 453 grams, and by previous calculation you know < ~> that the percent of solute is 60. Begin known data entry by keying < ~> in the value 625 followed by [enter]. At the prompt for the next < ~> two knowns, key in their values. < SOLVING THE EQUATION Equations are solved automatically once all knowns have a value. If you skip the entering of a value, you will return to the first value prompt. ~ ~> In our example, once you have entered the values or 625 ml for < ~> volume, 60 percent for solute percent and 453 grams for mass of < ~> solute, the equation is solved for you and the resulting density of < ~> 1.208 is displayed. < CHAINING FROM ONE EQUATION TO ANOTHER You can easily use values from one equation in solving another. Both entered knowns and calculated unknowns as well as calculated intermediate values are retained until cleared. The variables which currently have values are noted by an asterisk at the far right edge of the screen. Select a new equation and begin data entry by pressing [enter]. Existing values are displayed at the prompt. Use the existing values by pressing enter. ~ ~> For our example problem, use the up arrow to select molarity as the < ~> unknown for which to solve, then press the left or right arrow key < ~> until the knowns density, percent solute and solute molecular weight < ~> are selected. Since density and percent solute already contain < ~> values, press [enter] at the prompts to accept them. Enter 180.1577 < ~> as the molecular weight and the molarity value of 4.0231 will be < ~> calculated. < AUTOMATIC CALCULATION OF MOLECULAR WEIGHTS When the equation calls for the molecular weight of the solute or solvent, you can automatically link to the molecular weight function. When prompted for the molecular weight, instead of entering a numeric value, simply enter the formula of the substance. ~ ~> Repeat the previous calculation, but when you get to the molecular < ~> weight prompt, instead of keying in a value or accepting the < ~> existing value, key in the formula C6H12O6. As you begin entering < ~> the molecular formula instead of a numeric value, a window to the < ~> Molecular weight calculator opens and accepts your formula entry. < ~> When you conclude the formula entry, the molecular weight is < ~> calculated and placed in the corresponding entry field. It should < ~> now be obvious that we've been "fudging" with this example! < RECALCULATING WITH DIFFERENT VALUES It is easy to recalculate an equation while changing only one or more of the values. This allows "what if" calculations or corrections to be made with ease. ~ ~> Suppose, for instance, that in the example, the measured density of < ~> our fudge, when ready to eat, turns out to be 1.26. You could < ~> recalculate the molarity by substituting the new value for density < ~> while retaining the other values and determine that the final < ~> molarity of the fudge is 4.1963. < PERMUTING THE EQUATION Either before or after calculating the unknown value of an equation or entering any of the knowns, you can permute the equation. Press [pgup] or [pgdn] to rearrange an equation into the desired permutation. REVEALING ALL CURRENT VALUES During a calculation sequence, as the various equations are solved to arrive at the selected unknown, various intermediate values are calculated and stored. An asterisk in the right-most column of the variables window indicates that their is a value for that variable. Press [ins], the insert key to reveal all current values. EXCHANGING DATA WITH THE DILUTIONS CALCULATOR Solution volume and percent can be exchanged with the dilution calculator. See the instructions for the dilution calculator for an explanation. PRINTING OR STORING A REPORT Use the [alt-ƒ5] report function to send a report of the current equation and values to a printer port or to a file. If the equation variable have been supplied with some or all knowns or the unknown has been calculated, those values will be included in the report. If values are empty, the report will show blanks in their place, thus a printed report can be used as an entry form. Jot down values in the lab then return to the calculator to perform the calculations. DELETING CURRENT VALUES To delete all current values and begin a new solutions problem, press [delete]. All calculated and entered values will be erased, but the equation selection is unchanged. ________________________________________________________________________________ ■0815 SOLUTIONS CALCULATOR VARIABLES The Solutions Calculator accepts input values or calculates the values of: ┌─ molarity ü │ molality é solution ┤ normality â │ mass in grams ä │ density à └─ volume in ml å ┌─ equivalent weight ç │ number of equivalents ê │ percent in solution by weight ë solute ┤ valence è │ molecular weight ï │ mass in grams î │ moles ì └─ molar fraction Ä ┌─ molecular weight Å solvent ┤ mass in grams É └─ moles æ ______________________________________________________________________________ »üsolution molarity number of moles of solute per liter of solution. Abbreviated in formulas: sln_mlrty ______________________________________________________________________________ »ésolution molality The number of moles of solute per kilogram of solvent. Abbreviated in formulas: sln_mllty ______________________________________________________________________________ »âsolution normality The number of equivalents of solute per liter of solution. Abbreviated in formulas: sln_nrmty ______________________________________________________________________________ »äsolution mass in grams The total mass of the solution expressed in grams. Abbreviated in formulas: sln_grams ______________________________________________________________________________ »àsolution density The solution mass in grams divided by volume in milliliters. Abbreviated in formulas: sln_denst ______________________________________________________________________________ »åsolution volume in ml The total volume of the solution. Abbreviated in formulas: sln_volml ______________________________________________________________________________ »çsolute equivalent weight The gram molecular mass of solute divided by the number of solute reaction units. Abbreviated in formulas: slt_eqwgt ______________________________________________________________________________ »êsolute number of equivalents The number of reaction units per solute molecule. Abbreviated in formulas: slt_eqnum ______________________________________________________________________________ »ë%solute in solution by weight The percent of solute in solution by weight. Abbreviated in formulas: slt_pccon ______________________________________________________________________________ »èsolute valence The number of equivalents per mole of solute. Abbreviated in formulas: slt_valnc ______________________________________________________________________________ »ïsolute molecular weight The molecular weight of the solute compound. Abbreviated in formulas: slt_molwt ______________________________________________________________________________ »îsolute mass in grams The mass of the solute in solution in grams. Abbreviated in formulas: slt_grams ______________________________________________________________________________ »ìsolute moles The amount of solute relative to the amount containing the same number of molecules as in 12 grams of Carbon 12. Abbreviated in formulas: slt_moles ______________________________________________________________________________ »Äsolute molar fraction The moles of solute divided by the sum of moles of solute & moles of solvent. Abbreviated in formulas: slt_molfr ______________________________________________________________________________ »Åsolvent molecular weight The molecular weight of the solvent compound. Abbreviated in formulas: slv_molwt ______________________________________________________________________________ »Ésolvent mass in grams The mass of the solvent in solution expressed in grams. Abbreviated in formulas: slv_grams ______________________________________________________________________________ »æsolvent moles The amount of solvent molecules relative to the molar standard 12 grams of Carbon 12. Abbreviated in formulas: slv_moles ________________________________________________________________________________ ■■