Determine the reaction rate A + B = 2C, if the concentration of substance A for 20 minutes. changed by 0.025 mol / l.

Speed reaction:
v = ∆v / (V * ∆t), where ∆v is the change in the amount of substance, V is the volume of the substance, ∆t is the time.
The molar concentration is determined by the expression:
∆С = ∆v / V, we substitute in the first formula:
v = ∆v / (V * ∆t) = ∆С / ∆t.
Let’s convert time into seconds:
t = 20 min = 1200 s.
Substituting the numbers, we get:
v = ∆С / ∆t = 0.025 / 1200 = 2.08 * 10 ^ -5 mol / l * s.
Answer: the reaction rate is 2.08 * 10 ^ -5 mol / l * s.