Chemistry Chemical Kinetics

Reaction rate is used to measure how fast or slow reactions occur per unit time. The rate constant is a proportionality factor that remains constant for every reaction.

Yes, in elementary reactions, order and molecularity can be the same, but this is not always the case because order is an experimental quantity, and molecularity is a theoretical concept.

Reaction Kinetics, also known as chemical kinetics, is the study of the rate of chemical reaction and the factors affecting the reaction rate, such as temperature, concentration, and catalyst.

A ->2B + C

t = 0          a      0       0

t = 10       a – x  2x     x

t ->    $\infty$ 0       2a    a

$\therefore$ $\begin{array}{l}a+2x\propto 176\\ 3a\propto 270\\ a\propto 90\\ 2x\propto 86\\ x\propto 43\\ a-x\propto 90-43\\ a-x\propto 47\end{array}$                       

Temperature coefficient is 2 that means rate of reaction doubles at every 10°C rise in temperature.
Thus, k? °C = 2? = 64 k? °C

$\frac{d\left[C\right]}{dt}=\left(\frac{20-10}{10}\right)=1mmold{m}^{-3}$

$+\frac{d\left[D\right]}{dt}=\left\{-\frac{d\left(B\right)}{dt}\right\}*1.5=\frac{3}{2}\left\{-\frac{d\left[B\right]}{dt}\right\}$

$\left\{-\frac{d\left[B\right]}{dt}\right\}=2*\left\{\frac{-d\left[A\right]}{dt}\right\}$

$\therefore \frac{1}{6}\left\{\frac{-d\left[B\right]}{dt}\right\}=\frac{1}{3}\left\{\frac{-d\left[A\right]}{dt}\right\}=\frac{1}{9}\left\{\frac{+d\left[D\right]}{dt}\right\}=\frac{d\left[C\right]}{dt}$

$\therefore$ rate of reaction = $\frac{+d\left[C\right]}{dt}$  = 1m.m dm^-3 S^-1

K = 3.3 * 10^-4 s^-1

Time for 40% completion ; t

Using $K=\frac{2.303}{t}lo{g}_{10}\frac{{\left[R\right]}_0}{\left[R\right]}$  

3.3 * 10^-4 =   $\frac{2.303}{t}lo{g}_{10}\frac{{\left[R\right]}_0}{0.6{\left[R\right]}_0}$

  $t=\frac{2.303}{3.3}*10^4*0.22\Rightarrow t=25.58mins$            

so; the nearest integer is 26.

$K_{cat}=A{e}^{-}\frac{{\left(Ea\right)}_{cat}}{RT}and{K}_{uncat}=A{e}^{-}\frac{{\left(Ea\right)}_{uncat}}{RT}$

 $\frac{K_{cat}}{K_{uncat}}=e^{\frac{{\left(Ea\right)}_{uncat}-{\left(Ea\right)}_{cat}}{RT}}=e^{\frac{10*1000}{8.314*300}}=e^{4.009}=e^x$

$\therefore x=4$

A reaction can have zero activation energy, for example, •CH? + •CH? → CH? − CH? has zero activation energy.

Let the new rate be, R'.

A' = [3 A], B' = [B]

R' = K [A']² [ B']

= K [3 A]² [ B]

= 9 K [ A]² [ B]

= 9 * R

Hence, rate would become nine times.