Rate of Reaction Formula
The Rate of Reaction is proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time. And can be defined as,
- Rate of Reaction = Decrease in the concentration of a reactant R / Time Interval
- Rate of Reaction = Increase in the concentration of a product P / Time interval
If we consider, [R1] and [P1] are the molar concentrations of the reactant and the product respectively at any time t1 and [R2] and [P2] are the concentrations of reactant and product at time t2, then changes in concentrations of the reactant and product will be d [R] = R2 – R1 and d [P] = P2 – P1 and time interval is dt = t2 – t1 and the rate of reaction in terms of reactant or product is given by
- Rate of reaction = -(R2 – R2)/ (t2 – t1) = + (P1 – P2)/(t2 – t1)
- Rate of reaction = – Δ[R]/Δt =+ Δ[P]/Δt.
Significance of Negative and Positive Signs
The sign in the rate of reaction tells about the increase and decrease in the concentration.
- Negative sign indicates that the concentration of the reactant is decreasing.
- Positive sign indicates that the concentration of the product is increasing.
Expressing the Rate of Reaction in terms of different Reactants and Products
Let us consider a reaction ⇒ a A + b B ⇢ x X + y Y
Then the Rate of Reaction is given by
Rate = – 1/a d[A]/dt = – 1/b d[B]/dt = + 1/x d[X]/dt = + 1/y d[Y]/dt
where
- d[A], d[B] represent small decrease in the concentrations of A and B respectively
- d[X] and d[Y] represent small increase in the concentrations of X and Y respectively in the small interval of time dt
Rate of Reaction
Rate of Reaction or Reaction Rate in chemistry is defined as the speed or the rate at which a chemical reaction takes place. The rate of a Chemical Reaction is directly proportional to the increase in the concentration of a product per unit of time and to the decrease in the concentration of a reactant per unit of time. This can vary drastically. Chemical reactions proceed at extensively different speeds depending on the nature of the reacting substances, the type of chemical transformation, the temperature, and other factors.
In this article, you will understand the meaning of rate of a chemical reaction, rate of reaction order, the unit of the rate of reaction, and formulas.
Table of Content
- What is the Rate of Reaction
- Rate of Reaction Formula
- Average Rate of Reaction
- Instantaneous Rate of Reaction
- Unit of Rate of Reaction
- Factors Affecting Rate of Reaction