The Chemical Education Journal (CEJ), Vol. 9, No. 2 (Serial No. 17). The date of issue: January 30, 2007./Registration No. 9-14/Received March 7, 2006.
URL = http://www.juen.ac.jp/scien/cssj/cejrnlE.html

Automatic Services of Calculating Data and for the Preparation of Solutions by Using Internet
- Nitric Acid Aqueous Solution and Sulfuric Acid Aqueous Solution -

Minoru Ashida*, Makoto Shishido, Nobutaka Okajima, Elizabeth S. Escano and Takahiro Abe
Faculty of Education, Saitama University
255 Shimo-ohkubo, Sakura-ku, Saitama, Saitama, 338-8570 Japan
E-mail: ashida@post.saitama-u.ac.jp

I. Introduction
     Dislike of science is now spreading over students and even teachers in Japanese elementary schools. It seems that interest in science (chemistry) may often be generated through experiments. Therefore, we started an automatic service in the homepage of our chemical laboratory [ref. 1] on how to prepare aqueous solutions (calculating concentrations and preparation methods) [ref. 2, 3] which are the bases of some chemical experiment, in order to reduce dislike of science and to do various experiments using solutions prepared by teachers in elementary schools. Even a person who has no background in computers can use it anytime when it is necessary. Furthermore, we started a download service, so you can carry out this program even in a PC (offline) if you download a compressed file and extract it.
     On previous reports [ref. 2, 3], we discussed about sodium chloride aqueous solution, acetic acid aqueous solution, hydrochloric acid, ammonia water, and sodium hydroxide aqueous solution, and already started service in the homepage. In this report, we have developed the programs for nitric acid and sulfuric acid aqueous solutions, which would be very useful in the future, and we are planning to put it in the homepage as well. However, there are only few general users of this homepage service because it is not yet known very much. Therefore, we decided to make it known to many people through this report, and to have them use the service.

II. Operation manual for users
     We explain mainly about a preparation method of nitric acid aqueous solution. The initial screen (fig. 1) is displayed when you select and click "the nitric acid" from a menu of "preparation of solutions (including calculation of concentration and caution)". The initial screen (fig. 2) is displayed likewise when you chose sulfuric acid (an operation method is approximately similar in the case of the following nitric acid aqueous solution). With nitric acid aqueous solution, five textboxes of the left column are linked with five buttons of the central column. You input numerical value (for example, percentage concentration and volume of solution after dilution) into two textboxes to prepare an aqueous solution from the concentration and volume of aqueous solution after dilution and/or to calculate the concentration of aqueous solution after dilution from the volume of conc. nitric acid and diluent water before dilution. Then you push a right button of the empty textbox (for example, nitric acid volume of the central column). Even if a numerical value is entered into the left textbox of the button which you pushed then, it is not treated as the thing which is input. A program calculates numerical values of all the empty textboxes automatically and displays them by a green letter(fig. 3). It is also possible to have the inputs in an exponential form, such as 5.432E-1 and 1.234e5. Note, however, that no space is allowed to be inserted between the E (e) and the figures.
     Because we assume that the person who uses this program does not know a calculation method of the concentration, we have produced it to run as possible even if users operate it at random. The program can calculate, if you input numerical values into two textboxes like statement above, but the program runs even if you input more than three numerical values into textboxes. However, a calculation adopts only two numerical values. When you input more than three numerical values showing priority sequence similar to table 1 (priority sequence with other chemical reagents is similar to the case of nitric acid). It is desirable that the numerical value that was not adopted should not vary with the calculation. (In other words, the other numbers are not random numerical value). You can clear all the numerical values or calculated values with a button at the right column before calculating again. In addition, if you only change the last numerical value without the prior clearing of the existing numerical values and push the button, the value that you changed may not be adopted due to the priority sequence of adoption and the previous value may be displayed by the new calculation.
     Because conc. nitric acid comes in normal concentration (70%) and in fuming nitric acid (100%), so you can choose which of the two you are going to calculate by pressing the checkbox. That is why it will display a warning in red letters when a calculation exceeds these concentration 70% (15.6 mol/L) or 100% (23.9 mol/L) (fig. 4). When you convert the concentration (for example, from the percentage concentration to molarity), you input the numerical value into textbox of either; then, you push the right button of the other textbox (fig. 5). In addition, an error message is displayed when you cannot calculate the operation by mistake (fig. 6). Numerical value slightly changes when you push any button randomly in the state that a calculation is finished. This is the error caused to change the calculation method by priority sequence or round off numerical value for display.

III. Preparation method and precautionary measures for aqueous solutions of strong acids
     We put the following concrete preparation methods and caution for safety on our homepage as well as the programs of Java Applet. In addition, we put photographs and usage of main experimental apparatus. We describe the case of nitric acid aqueous solution (fig. 1) as follows. It is almost similar to sulfuric acid aqueous solution (fig. 2).

    Wash and dry the necessary apparatus beforehand.
1 Measure the desired amount of distilled water using a measuring cylinder (fig. 7), then transfer it to a beaker.
2 Measure conc. nitric acid aqueous solution with another measuring cylinder (fig. 7), and add slowly it into the distilled water in the beaker while stirring.
3 If necessary, transfer the solution to a reagent bottle and keep it. Attach label showing the reagent's name, concentration, the date of preparation, and the name of the person who prepared the solution.

    HNO₃ gas evaporates from conc. nitric acid aqueous solution to the space (air) above the solution in a bottle. So, the bottle of conc. nitric acid is filled with HNO₃ gas. When you open the bottle, the cover spray may appear. Be careful that neither gas nor mist gets in contact with the eyes. Moreover, the gas is toxic and it has a pungent smell. Work in a well ventilated place so that the gas may not be inhaled. If conc. nitric acid gets in contact with the eyes or is stained with the skin, immediately wash it with water. Keep in mind that heat is generated when conc. nitric acid is diluted with water. In adjusting the total volume of solution, do it after cooling the solution. The presumed concentration of reagent grade chemicals is near saturation (about 70%). When the exact concentration of dilute nitric acid solution is required, titrate it against a solution of a base of known concentration, i.e., a standard solution; then, you can determine its exact concentration.

IV. Calculation method
     We explain the following calculation methods [ref. 4, 5] in the homepage. Please note that the case of nitric acid aqueous solution (fig. 1) is almost similar to that of sulfuric acid aqueous solution (fig. 2).

    M_a = V_aD_cW_c/100,   M_b = V_b+V_aD_c(100-W_c)/100,   W = 100M_a/M,

    M = M_a+M_b = V_aD_c+V_b = VD,   C = 1000M_a/FV,   Q = V/V_b,   1L = 1000mL

where V_a(mL), W_c(%) and D_c(g/mL) are volume, mass percentage and density of conc. HNO₃ aqueous solution before dilution, M_a(g) mass of dissolved HNO₃ gas, V_b(mL) volume of diluent water before dilution, M_b(g) mass of total water, M(g), V(mL), W(%), C(mol/L), and D(g/mL) mass, volume, mass percentage, molarity, and density of solution after dilution, Q volume of solution after dilution/volume of diluent water before dilution, F(g/mol) formula weight of HNO₃. An unknown value can be calculated with the use of expressions shown above and known values. You may use table 2 [ref. 6] to find the density from the concentration and to find the concentration from the solution volume/diluent water volume. In addition, the value of solution volume/diluent water volume at the concentration of 70% or 100% should become infinite, but we replace the value with a very big value (5000 or 10000) to prevent a serious error in the program running.

V. Software used
     The OS used were Microsoft Windows 98, 2000 Professional, ME, XP home edition. Java Applet programs were produced with JBuilder 6 Professional of Borland [ref. 7-12], and uploaded through FFFTP 1.88 (free software) [ref. 13]. The HTML files were created and edited with Homepage Builder 2001 of IBM [ref. 14, 15] or Macromedia's Dreamweaver MX [ref. 16]. Stirling 1.31 (free software) [ref. 17] was used to edit the binary files of executable type.
     The descriptions of the constitution of files and development of the programs were omitted, as they were already included in our previous reports [ref. 2, 3]. However, the distribution file for downloading was changed into an applet jar type in order to compress the button and textbox class files into a single file.

VI. Conclusion
     The programs for calculating concentration and preparation method are now available not only in the internet servers at Saitama University but also for outsiders (ref 1). These can be used for lesson plan preparations and other forms of research. Eventually, more services for preparation of aqueous solutions will be available in the near future.

References(URL are at 22/02/2006.)
[ref. 1] Top Page of Chemical Laboratory http://www.e-sensei.ne.jp/~ashida/index.htm
    and http://www1.edu.saitama-u.ac.jp/users/ashida/index.htm
    and http://www.saitama-u.ac.jp/ashida/index.htm
[ref. 2] Minoru Ashida, Mayumi Igarashi, Hiromi Mutai, and Toshihisa Yoshida, "Automatic Services of Calculated Data and Preparation of Solutions by using Internet - Sodium Chloride Aqueous Solution -", The Chemical Education Journal (CEJ), Vol. 7, No. 1 (Serial No. 12)/Registration No. 7-5(2003) (in Japanese).
[ref. 3] Minoru Ashida, Hiromi Mutai, and Mayumi Igarashi, "Automatic Services of Calculated Data and Preparation of Solutions by Using Internet - Acetic Acid Aqueous Solution, Hydrochloric Acid, Ammonia Water, and Sodium Hydroxide Aqueous Solution -", The Chemical Education Journal (CEJ), Vol. 8, No. 1 (Serial No. 14)/Registration No. 8-3(2004) (in Japanese).
[ref. 4] Tetsuo Nakagawa, "Interconversion Formula for the Concentrations of Binary System Solution", Science Education Monthly, Vol. 51, No. 6, pp. 46-47 (2002) (in Japanese).
[ref. 5] Tetsuo Nakagawa, "Useful Expressions for the Adjustment of Aqueous Solutions", Science Education Monthly, Vol. 51, No. 10, pp. 44-45(2002) (in Japanese).
[ref. 6] Chem. Soc. Jpn ed., "Handbook of Chemistry, basic version II", Maruzen, 1993 (in Japanese).
[ref. 7] Kazuya Takahashi, et. al., "500 Tips to Use Java Better !", Shuwasystem, 2002 (in Japanese).
[ref. 8] Syuji Tanaka, "Introduction to JBuilder5 ! Java Programming", Sotechsha, 2001 (in Japanese).
[ref. 9] Kenichirou Matsuura and Yuki Tsukasa, "JBuilder6 First", Softbank Pub., 2002 (in Japanese).
[ref. 10] Seiki Akama, "Numerical Calculation with Java 2", Gihoudou Pub., 1999 (in Japanese).
[ref. 11] Masaki Aono, "Computer Graphics Learning with Java", Ohmusha, 2002 (in Japanese).
[ref. 12] Shigeru Nakayama, "Introduction to Java 2 Graphics Programming", Gihoudou Pub., 2000 (in Japanese).
[ref. 13] http://www2.biglobe.ne.jp/~sota/
[ref. 14] "Home Page Builder 2001 User's Guide", Japan IBM Corp., 1999 (in Japanese).
[ref. 15] ANK Software, "HTML Tag Reference", Shoeisha, 2000 (in Japanese).
[ref. 16] "Dreamweaver MX First Step Guide", Macromedia, Inc., 2002 (in Japanese).
[ref. 17] http://www.vector.co.jp/soft/win95/util/se079072.html

CEJ Vol. 9, No. 2, Contents