Physical chemistry Essay Example | Topics and Well Written Essays - 2000 words

Physical chemistry - Essay ExampleAn understanding of the Le Chateliers principle and catalysis is innate for proceeding with this study.Increase in temperature Exothermic reaction favours reactants, as the heat is absorbed to counterbalance the ontogeny in temperature. Endothermic reaction favours products as the absorbed heat facilitates a larger amount of reactants to replace to products (Atkins & de Paula, 2006).Change in reactant constriction An increase in tightness of a reactant in a ever-changing equilibrium causes the reaction to favour products, as the excess reactant reacts with other reactants. A slump in concentration of a reactant favours the reverse reaction as the products are converted to reactants in order to balance the decrease in reactant concentration. (Clark, 2002 Morrison & Boyd, 1992)Change in product concentration A decrease in product concentration favours the forward reaction to balance the decrease. An increase in product concentration favours the r everse reaction. (Atkins & de Paula, 2006)Change in pressure Increasing the pressure of a system at equilibrium causes changes in the partial(p) pressures of reactants and products. The come out constant is independent of the change in pressure of a system, but depends on ratio of partial pressures of the reactants and products. The reaction moves in the direction where number of moles is less. (Atkins & de Paula, 2006)A catalyst accelerates a chemical reaction without undergoing a net chemical change. The catalyst reduces the energy of activation by altering the path of reaction to forefend the rate determining step, which is the slowest step in a reaction (Atkins & de Paula, 2006). For example, decomposition of hydrogen peroxide, which is a slow reaction at room temperature, requires activation energy of 76 kJ/mol. In the presence of iodide ions, this activation energy drops to 57 kJ/mol and rate constant