2. At an increased temperature, the molecules gain energy and therefore their speed is increased. This results in the increment in the number of collisions and hence the rate of reaction. Increasing the temperature also increases the kinetic energy of the reactants but the activation energy remains constant.
As the activation energy decreases the rate of reaction increases. So the rate of the reaction would be fastest for the reaction with minimum activation energy (Ea = 10 kJ/mole).
19. From the data it can be seen that as the concentration of Br2 is doubled keeping the concentration of NO constant, the rate of reaction is doubled. This means that the reaction is first order with respect to Br2.
20. From the data it can be seen that as the concentration of reactant A is increased to 4 times, keeping the concentration of B and C constant, the rate of the reaction increases by 4 times. This means that the reaction is first order with respect to A.
Similarly when the concentration of reactant A is increased to twice the value and that of reactant B is also increased to twice the value, keeping the concentration of reactant C constant, the rate of reaction increases to twice the value. As this increment is attributed to reactant A therefore the order of the reaction with respect to B is zero.
2. According to the Le Chatlier's principle, for a exothermic reaction if the temperature of the reaction is increased the value of the equilibrium constant decreases. As the equilibrium constant decreases the concentration of products is lowered.