Synthèse de Cannizzaro, bac Métropole 2021.

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Lisrel 8.80 -

There is no live preview. No automatic graph. You want a path diagram? You run a separate program—PRELIS for data prep, then LISREL for modeling, then a post-hoc diagrammer. The friction is high, but the reward is clarity. Every number in that output file was hard-won. Today, LISREL 8.80 lives on in dusty university servers, on ancient Windows XP virtual machines, and in the hearts of senior methodologists who swear by its numerical stability. “R’s lavaan gave me a Heywood case,” they say. “Mplus converged, but I didn’t trust it. LISREL 8.80? It failed gracefully. It told me exactly why my model was junk.”

And that is the quiet magic of LISREL 8.80. It never pretended to be easy. It never apologized for requiring a deep understanding of identification, scaling, and matrix dimensionality. It was a tool for the few who wanted to wrestle with causality at the level of population covariance matrices. In an era of drag-and-drop, black-box AI, firing up LISREL 8.80 feels almost like a religious act—a reminder that sometimes, the most powerful insights come from the simplest, strictest dialogue between a human and a command line. lisrel 8.80

Here’s an interesting piece on , a piece of software that once sat at the very peak of the social sciences’ statistical toolbox. The Last Great Hermit of Statistical Computing: Why LISREL 8.80 Still Matters In an age where data scientists casually pipe Python commands into cloud-based GPU clusters, there exists a quiet, gray-bearded piece of software that refuses to die. Its name is LISREL 8.80 —a version number that sounds less like a modern app and more like a forgotten radio frequency. Released in the mid-2000s, 8.80 was the apex of a lineage that began in the early 1970s, crafted by Karl Jöreskog and Dag Sörbom at Uppsala University in Sweden. To use LISREL 8.80 today is to step into a time capsule—one filled with command-line syntax, three-letter variable names, and a stubborn, almost beautiful, lack of a point-and-click interface. The Hermeneutics of Syntax Most researchers open SPSS or R and drag variables into boxes. In LISREL 8.80, you write a script. Not an R script or a Python notebook, but a .SYM or .SPL file where every character matters. The language is terse, almost poetic: There is no live preview

So here’s to LISREL 8.80: the last great hermit of statistical computing. Still running. Still correct. Still refusing to offer a dark mode. You run a separate program—PRELIS for data prep,

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3.1. Effectuer un schéma légendé de l'ampoule à décanter en précisant les phases présentes et leurs compositions respectives après décantation.

lisrel 8.80
3.2. Justifier le choix de l'éther éthylique.
L'eau et l'éther ne sont pas miscibles.
Le produit A, alcool benzylique, est très soluble dans l'ether et très peu soluble dans l'eau.
Le produit B, ion benzoate, est très soluble dans l'eau et insoluble dans l'éther.
3.3. Justifier que l'on veuille obtenir un pH inférieur à 2 pour la phase aqueuse.
pKa( acide benzoïque / ion benzoate = 4,2.
A pH < 2, l'acide benzoïque prédomine et celui-ci est insoluble dans l'eau.
3.4. Donner l'intérêt du bain de glace et d'eau.
La température de ce bain est égale à 0°C. La solubilité de l'acide benzoïque est très faible à °C.
3.5. Citer une technique permettant d'isoler le produit B de la phase aqueuse.
Filtration sur büchner.
3.6. En utilisant le chromatogramme, conclure sur l'efficacité de l'étape de séparation des produits.
3.7. En utilisant le chromatogramme, conclure sur la pureté des produits.
Le produit A n'est pas pur : il contient du benzaldehyde et de l'alcool benzylique.
Le produit B est pur, on l'identifie à l'acide benzoïque.


  
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