If for a first-order reaction, $[A]_0 = 1.0\ \text{M}$ and $[A]_t = 0.25\ \text{M}$ after 276 s, find the value of the rate constant (k).

The equation for the rate constant is $k = Ae^{-E_a/RT}$.
A chemical reaction will proceed more rapidly if there is a decrease in

What is the oxidation state of chromium in the final product when KI reacts with acidified potassium dichromate solution?

Which of the following series of transition elements has general electronic configuration, $[\text{Kr}]\,4d^{1-10}\,5s^{0-2}$?