CHEMISTRY COMMUNITY

Can someone explain what exactly is the rate constant?

The rate constant k is just an experimentally determined value for a specific reaction at a specific temperature (therefore different reactions have different rate constants). It is also independent of concentration or concentration change. Unless temperature (and/or activation energy) changes, k will remain the same. Therefore, it limits the reaction rate: the higher the k value, the faster the reaction proceeds (therefore making the reaction rate higher).

Also, rate constants are dependent on temperature and activation energy.

The rate constant's units are also dependent on the order of the reaction.

- As temperature (T) increases, k increases
- As activation energy (E_a) increases, k decreases
- As frequency factor (A) increases, k increases

The rate constant is an experimentally determined value for a specific reaction at a specific temperature. It essentially tells you the instantaneous rate of change.

instantaneous rate of change