Donald D.Hedberg Chemical Predictor

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Country of manufacture: USA,            Date of manufacture: >= 1955
Diameter: 24.5 cm,      Weight: 90.5 gms
Materials: all plastic
Cursor: two, radial. Larger one for selecting reactions, smaller one for EMF to free energy conversions.
Outer Disk: Oxidation equations Oxidation Potential
Intermediate Disk: Reduction equations, Reduction Potential
Center Disk: conversion of E.M.F. values to equilibrium constants or free energy
Back: Correction factor scale for the standard potential at different solution concentrations, instructions for use.
Condition: C5 (Normal signs of use)
Came with: Nothing
Note: Compare this version with the somewhat later one produced by the Graphic Calculator Company, here.

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