Question 4(a)Half-life (t1/2) of the reaction is constant.(b)Draw the tangent to the graph at point P (as shown in Figure 1a).
(c)Draw tangents to the graph at 5 or more different [reactant]. Find the gradients as described in (b)
Standard QuestionsQuestion 1(a)Comparing results of experiments 1 and 2, when [Y] increases 3 times, rate of increase in [XY2] increases by 9 times ⇒order of reaction with respect to Y is 2.Comparing results of experiments 1 and 5, when [X] increases 3 times, rate of increase in [XY2] remains the same ⇒order of reaction with respect to X is 0.(b)Rate = k[Y]2Overall order of reaction = 2(c)Using results from experiment 1, 0.0001 = k(0.10)2⇒k = 0.01 mol-1dm3s-1(d)Using value of k calculated from (c), rate = 0.01[Y]2For experiment 6, 0.0036 = 0.01a2⇒a = 0.00360.01=0.60For experiment 3, b = 0.01(0.30)2= 0.0009(e)Hence, mechanism 1is consistent with the observed kinetics.Question 2 Rate = k[A]2[B], original rate = R= k[A]02[B]0 where [X]0 = initial [X]Qn.(a)(b)(c)(d)(e)ChangeDouble partial pressures of A & BPartial pressure of A doubled.Double volume of reacting vessel.Double total pressure with inert gas.30°C increase in temperature.New rate8R4R⅛RR8RReasonDoubling partial pressure ≡doubling concentration