The ASTM Computer Program for Chemical Thermodynamic and Energy Release Evaluation CHETAH®, Version 11.0
The CHETAH (Chemical Thermodynamic and Energy Release) program is a unique tool for predicting both thermochemical properties and certain "reactive chemicals" hazards associated with a pure chemical, a mixture of chemicals, or a chemical reaction. This is accomplished through a knowledge of only the molecular structure(s) of the components involved by an implementation of Benson’s method of group additivity. CHETAH is useful for classifying materials for their ability to decompose with violence, for estimating heats of reaction or combustion, predicting chemical equilibrium, and for predicting lower flammable limits.
CHETAH can be used to perform the following functions by simple menu selections:
- Classify a material or mixture with respect to its ability to decompose with violence when subjected to severe impact.
- Predict CHEMICAL EQUILIBRIUM for a mixture of reactants
- Calculate the ENTHALPY OF COMBUSTION for a compound or mixture
- Calculate THERMOCHEMICAL PROPERTIES for REACTIONS: .Cprxn, .Hrxn, .Srxn, .Grxn, logK
- Calculate THERMOCHEMICAL PROPERTIES for COMPOUNDS: Cp, S, .Hf, .Gf, logKf, Free Energy Function (G-H)/T, HT-H298
- Estimate LOWER FLAMMABLE LIMITS, and other flammability properties
- BUILD COMPOUNDS from library or user-entered groups for gases, liquids, or solid crystals
- BUILD CRYSTALS from ionic groups
- Enter PRIVATE THERMOCHEMICAL DATA (Benson groups, gases, solids, or liquids)
- View THERMOCHEMICAL DATA in CHETAH's database
- Modify previous CHETAH sessions
- Generate reports.
Areas that are beyond the scope of this program include:
- CORRECTION OF IDEAL GAS VALUES TO LIQUID OR SOLID PHASES%nbsp; This version of CHETAH can predict thermodynamic properties of solids and liquids using a predictive method based on Benson’s method. However the most general predictive method is based on ideal gas values. Many compounds can only have their properties predicted as ideal gases in CHETAH. This program cannot correct the ideal gas values back to condensed values. This can be an important consideration when calculating heats of reactions. Accurate heats require true representation of the states of reactants and products. In some cases, the gas phase heat of reaction may not differ significantly from the condensed phase value due to a cancellation of corrections. NOTE: The hazard evaluation portion of CHETAH (ERE option) classifies materials in the condensed state based on gas phase thermodynamic properties. This is feasible because the correlations used by CHETAH were developed using data that were measured for condensed phase materials and because phase transition energies are small with respect to the amount of energy that is required to generate a violent explosion. CHETAH uses gas state thermodynamics to classify materials that are in any of the gas, liquid, or solid states
- KINETICS CHETAH cannot predict rates of chemical reactions in the classic sense of determination of Arrhenius parameters.
Stock #: DS51HOL