Si on admet qu'à Bruxelles, à Marseille, à Montréal, à Paris...

Si on admet qu'à Bruxelles, à Marseille, à Montréal, à Paris ou à Tunis, il faut trois minutes pour faire cuire un cuf à la coque, quel est le temps de cuisson nécessaire, à $1800 \mathrm{~m}$ d'altitude où la température d'ébullition de l'eau peut être estimée à $93,4^{\circ} \mathrm{C}$ ? On admettra que l'énergie d'activation de la réaction de cuisson de l'œuf (assimilable à la coagulation de l'albumine) est de $120 \mathrm{~kJ} / \mathrm{mol}$.

Si on admet qu'à Bruxelles, à Marseille, à Montréal, à Paris ou à Tunis, il faut trois minutes pour faire cuire un cuf à la coque, quel est le temps de cuisson nécessaire, à $1800 \mathrm{~m}$ d'altitude où la température d'ébullition de l'eau peut être estimée à $93,4^{\circ} \mathrm{C}$ ?
On admettra que l'énergie d'activation de la réaction de cuisson de l'œuf (assimilable à la coagulation de l'albumine) est de $120 \mathrm{~kJ} / \mathrm{mol}$.

Key Concepts

Boiling Point Variation with Altitude

The boiling point of water is not constant but varies with atmospheric pressure, which decreases with elevation. At higher altitudes, water boils at temperatures lower than 100 °C. This reduction in boiling temperature impacts cooking processes by lowering the rate of chemical reactions, necessitating adjustments in cooking times.

Reaction Kinetics

Reaction kinetics deals with the rates of chemical processes and how various factors, like temperature and activation energy, influence these rates. In culinary processes such as cooking eggs, reaction kinetics explains why cooking times can vary with temperature, as the rate of protein denaturation and coagulation depends critically on the kinetic parameters.

Arrhenius Equation

This fundamental relation in chemical kinetics describes how the rate of a chemical reaction depends on temperature. It shows that the reaction rate constant increases exponentially as the temperature rises, which is captured by the equation k = A exp(–Ea/(RT)), where Ea is the activation energy, R is the gas constant, and T is the absolute temperature.

Activation Energy

Activation energy is the minimum energy barrier that must be overcome for a chemical reaction to occur. In the context of cooking, a higher activation energy implies that even a small reduction in temperature can significantly slow down the reaction rate, affecting how quickly the food undergoes the desired transformations, such as protein coagulation.

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