For a reaction $A products$ the half-life is $600 s$ at $[A]_{0} = 0.10 mol L^{- 1}$ and $300 s$ at $[A]_{0} = 0.40 mol L^{- 1}$ . Using $t_{1/2} \propto [A]_{0}^{1 - n}$ , find the order $n$ (two decimals).

Numerical answer type, tolerance 0.02.

Answer: 1.5

t_{1} / t_{2} = ([A]_{0, 2} / [A]_{0, 1})^{n - 1}

gives

600/300 = 4^{n - 1}

. Hence

n - 1 = lo g 2/ lo g 4 = 0.5

and

n = 1.50

(fractional orders are possible).