The water in a pressure cooker boils at a temperature greater than 100°C because it is under pressure. At this higher temperature, the chemical reactions associated with the cooking of food take place at a greater rate. (a) Some food cooks fully in 5 min in a pressure cooker at 112°C and in 10 minutes in an open pot at 100°C. Calculate the average activation energy for the reac- tions associated with the cooking of this food. (b) How long will the same food take to cook in an open pot of boiling water in Denver, where the average atmospheric pressure is 0.818 atm and the boiling point of water is 94.4°C?

What is the fraction of collisions that have sufficient energy for reaction if the activation energy is 50 kJ mol−1 and the temperature is (a) 25°C, (b) 500°C?

A certain reaction has an activation energy of 58.70 kJ/mol. At what Kelvin temperature will the reaction proceed 7.00 times faster than it did at 287 K? T=

Given the following values of the enthalpy (DH) and activation energy (Ea) of four different reactions, identify an exothermic reaction that would exhibit the fastest rate at 298 K. (Assume that all reactants have the same initial concentration and the same Arrhenius frequency factor A in k = Ae-Ea/RT).   (A) DH = +45 kJ/mol;    Ea = 75 kJ/mol;             (B) DH = +35 kJ/mol;    Ea = 65 kJ/mol; (C) DH = -35 kJ/mol;     Ea = 75 kJ/mol; (D) DH = -45 kJ/mol;    Ea = 65 kJ/mol;