can you fix the grammar

Rate of reaction refers to speed of the concentration of reactant convert to product the formula states [A] concentration of reactant, (-)= the concentration going down overtime and t=time.

The rate of reaction refers to the speed at which the concentration of a reactant converts to a product. The formula can be stated as [A] (-)= the concentration decreasing over time, with t representing time.

Here is the corrected version of the sentence:

"The rate of reaction refers to the speed at which the concentration of reactant converts to product. The formula can be stated as [A] (concentration of reactant) decreasing over time (t)."