For the second-order reaction below, the initial concentration of reactant a is 0.24 m. if the rate constant for the reaction is 1.5 x10–2 m–1s–1, what is the concentration of a after 265 seconds? 2a --> b + crate = k[a]20.12 m0.19 m0.95 m4.0 m5.2 m

Concentration of A after 265 seconds is 0.12 M

Explanation:

Integrated rate law for the given second order reaction is-

where [A] is concentration of A after "t" time, is intital concentration of A and k is rate constant.

Here is 0.24 M, k is 0.015 and t is 265 S

Plug in all the values in the above equation-

                              or, [A] = 0.12

So concentration of A after 265 seconds is 0.12 M

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"