2. Во сколько раз изменится скорость прямой реакции 2А + В А2В, если концентрацию вещества А увеличить в 3 раза, а концентрацию вещества В уменьшить в 3 раза?
To solve this problem, we need to use the law of mass action, which states that the rate of a chemical reaction is directly proportional to the concentration of the reactants. In this case, we have two reactants, A and B, and the final product A2B. The rate of the reaction can be expressed as r=k[A]^2[B]. By increasing the concentration of A by 3 times and decreasing the concentration of B by 3 times, we are essentially altering the values of [A] and [B] in the rate equation. This will result in a change in the rate of the reaction. To determine the exact change in rate, we can use the concept of reaction rates and equilibrium constants. So, according to Le Chatelier's principle, if we increase the concentration of one reactant while decreasing the concentration of another, the reaction shifts towards the side with less concentration. This means that the reaction will be favored in the forward direction, leading to an increase in the rate of the direct reaction 2A + B --> A2B. To quantify this change, we can calculate the new rate of the reaction by substituting the new values of [A] and [B] in the rate equation. Therefore, the new rate can be expressed as r'= k'[A']^2[B']. To find k', we can use the equilibrium constant K' = ([A'][B'])/([A][B]), which is equal to 1/(K*K). Thus, we can calculate the new rate as r'=k'/K^2[A]^2[B]. Since K' is equal to 1/9 of K, the new rate of the reaction will be 9 times greater than the original rate. This means that the speed of the reaction will increase by 9 times. In other words, the reaction will be 9 times faster than before. Therefore, to answer the initial question, the speed of the direct reaction 2A + B --> A2B will increase by 9 times when the concentration of A is increased by 3 times and the concentration of B is decreased by 3 times.
