Chemiccrl Educcrtion: Softwnre Abstract for JCE: Software, Volume IIIA. Number 2
Buoyancy Programs
Bomb Calorimeter Simulation
This program simulates experimental measurement of rhe density of solids, liquids, and mixtures of liquids. "Huoyancy I'rozrilms" can be usrd as a Ierrure aid in illustratine the principles of buoyancy, as a pre-laboratory exercise to familiarize students with the ~rincinlesof huovancv. or as a simulated experiment. ~ f t e r shok, optiona~;liscidsionand derivation of the equations used to calculate densitvfrom buovancy measurements, a student is prompted to choose an experiment to measure the density of solids, liquids, or a mixture of two liquids. In the density-of-solids experiment three sample sizes are available; the weight of the sample is recorded in air and then with the sample immersed in water. In the density-ofliquids experiment, 18 sample liquids are available, and temperature can be controlled; the weight of a solid is recorded first in air and then when immersed in the selected liquid. From the data students can calculate the density of the solid or the liquid. T o determine the density of a mixture of two liquids, the student first selects one of five mixtures and enters a temperature. Solutions may then he prepared by weight or by volume. The weight of a solid is then recorded in air and when immersed in the liquid mixture. The student can review the mixture for which measurements were taken, choose another liquid mixture system, or make a different mixture from the current selected system. From the measurements taken, the molar volumes of the mixture can be calculated, which may then be used to calculate the excess volumes and/or partial volumes.
David J. Olney Lexington High School Lexington, MA 02173 The mathematics involved in analysis of calorimetry data is simple enough for high school students, but the equipment is not widely available. Thus, bomb calorimetry proves worthwhile for computer simulation. The program begins with a short introduction and then presents a graphic of the experimental apparatus. Labeled nictures of the homh calorimeter., oxveen tank., water ~~~-bath. ~~~~~"ignition switch, and thermometer are presented to show how the e a u i ~ m e nist assembled. A student first chooses a known or unknown chemical and weighs a sample. The calorimeter constant is then determined from a simulated experiment or provided by the computer, which chooses randomly from a range of values. Once determined, the constant will not change until the simulation is restarted. The sample is then placed in the bomb and the homh is charged with oxygen. An amount of water entered by the user provides the water hath and the calorimeter is lowered into the water hath. A stirring bar and thermometer are placed in the bath, and the water hath is allowed to equilibrate a t a desired temperature. The fuse wire is attached to the ignition switch, and the sample is ignited. Finally, the highest attained temperature of the water bath is measured and recorded. If a printer is available, data from an experiment can be printed. The program has nine known samples and eight unknown samples. Heats of combustion were taken from the CRC Handbook1. If the student chooses an unknown. the nroeram provides a code number that the teacher can d&od;to I'dentifv the substance. Documentation includes user directions. teacher directions, and an experiment handout for studen& that the author has assigned to his honors high school chemistry class.
Hydrogen Atom Orbitals Michael Liebl Mount Michael Benedictine High School Eikhorn, NE 68022 "Hydrogen Atom Orbitals" first presents an optional short discussion of Schroedinger's equation and its solution for hydrogen atomic orhitals. Three types of solutions are available: the radial function, the spherical harmonic function, and the total wave function. These may be chosen from a menu. Choices for the radial function are: Is, Zs, Zp, 3s,3p, and 3d; for the spherical harmonics they are s, p,, p,, p,, d,,, d,,, d,,, d12y2, and d,z. If the total solution is chosen, a contour map, pseudo-3D map, or 3D map can be selected. Once a graphic has been displayed, program functions are chosen from a pop-up menu that is toggled on and off with the space bar; n and 1quantum numbers, orbital designation, and energy can be also displayed. All of the graphics can be saved to disk, thus allowing them to be imported into a painting program or printed using a printing utility program. 922
Journal of Chemical Education
Gary L. Bertrand University of Missouri-Roiia Roiia, MO 65401
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About This Issue John W. Moore and Jon L. Holrnes University of Wisconsin-Madison Madison, Wi 53706 This issue of JCE: Software for Apple I1 computers consists of three programs that cover diverse topics. The simulated homh calorimeter exposes students to some of the methodology and data analysis involved in calorimetry experiments. "Hydrogen Atom Orbitals" gives students a graphic representation of radial, spherical harmonic, and total solutions of Schroedinger's equation; it should help students to connect quantum numhers and the shapes of hydrogenic orhitals. "Buoyancy Programs" develops the ideas of buoyancy and density; students make simulated buoyancy measurements and determine the density of various solids, liquids, and mixtures of liquids. In addition to these three programs, instructions nre presented, along with AppleWorks templates, to import data files from "The Computer-Based L a b o r a t ~ r y "into ~ AppleWorks. Doing so allows users of the thermistor and Blocktronic I1 to manipulate acquired data using the AppleWorks spreadsheet and associated third-party graphing programs.
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CRCHandbookof ChemisttyandPhysics;Weast, R. C.. Ed.: CRC: Cleveland, 1985. Krause, D. C. JCE: Soft 1988, /A (2).
Hardware Requlrernents
The programs in this issue are supplied on 5.25-in., DOS 3.3 format disks. They require an Apple IIe computer with a t least 64K RAM, a IIc, or IIcs. At least one 5.25-in. disk drive
is required. For "Hydrogen Atom Orbitals" two disk drives are more convenient and a color monitor is optional; for "Bomb Calorimeter" a printer is useful; and for "Buoyancy Programs" a color monitor is optional.
Volume 67
Number 11
November 1990
923
