Question

The rate constant for the decomposition reaction of H2O2 is 3.66 × 10−3 s−1 at a particular temperature. What is the concentration of H2O2 in a solution that was initially 10.0 M H2O2 after 15.0 minutes have passed?

Answer 1

Answer:  3.72 M

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = $3.66\times 10^{-3}s^{-1}$

t = age of sample = 15.0 minutes

a = let initial amount of the reactant  = 10.0 M

a - x = amount left after decay process = ?

$15.0\times 60s=\frac{2.303}{3.66\times 10^{-3}}\log\frac{10.0}{(a-x)}$

$\log\frac{100}{(a-x)}=1.43$

$\frac{100}{(a-x)}=26.9$

$(a-x)=3.72M$

The concentration of $H_2O_2$ in a solution after 15.0 minutes have passed is 3.72 M