The rate of a chemical reaction is a measure of how fast the reactants are being used up and how fast the products are being made. Reactions in which a gas is produced can be used to monitor the rate.

the faster the rate of a reaction. This is called the 'collision theory'. There are four factors that affect the rate (speed) of a chemical reaction: ...

In the course of work on the kinetics of this solid state reaction, the problem arose of deducing the reaction constant and the activation energy without exact knowledge of the reaction mechanism ...