The racemization of pinene is a first-order reaction. In the gas phase, the specific rate constant was found to be 2.2 x 10-5 min-¹ at 457.6K and 3.07 x 10-³ min-¹ at 510.1K. From these data estimate the energy of activation. 27,658 cal/mol 33,100 cal/mol 43,600 cal/mol None of the choices 37,700 cal/mol

The hydroxyl radical in the atmosphere is most effectively removed by hydrocarbons such as methane according to the second-order reaction below. •OH + CH4 - H20 + CH3' Given that the second-order rate constant is 3.0x106 L·mol-1.s-1, calculate the lifetime of the radical at 19°C if the concentration of CH4 is 1.5×103 ppb by volume. (Hint: The lifetime of the radical is given by 1/k[CH4].) 4.0 3.6e-3 X S

Which of the following is the integrated rate law for second-order reactions? [A] = [A]oe-kt O 1/[A] = 1/[A]o + kt O [A]o /2k O [A] = [A]o – kt

A certain first order reaction has k = 2.51 s-1 .  If the initial concentration of the reactant is 6.50 M, how much will be left after two half lives (in M)? Give your answer to three sig figs